Statcast Documentation

Christmas came a month early, apparently. Documentation of variables found on Baseball Savant’s Statcast search has been released.

Some of the key pieces of information in the documentation are strikezone zone locations and location of measurement of some variables (velocity and acceleration in x-y-z directions). Have at it!


– tb


What’s Hurting Bumgarner?

Something happened to Madison Bumgarner. His four-seam fastball went missing. Depending on which data source you use, it figuratively and literally disappeared. Regardless of data source used, Bumgarner’s fastball isn’t performing.

Two leading data sources disagree on what has happened to Bumgarner’s fastball. Because of this, I chose to look at both sources independently: Pitch Info (through Brooks Baseball) and Statcast (through Baseball Savant). This analysis spans four seasons, 2015 through 2018, encompassing Bumgarner’s two-best and two-worst complete seasons.

According to Pitch Info, Bumgarner threw four-seamers in 2018 at a career-low frequency – 34.5% of the time in 2018, down from 48.2% in 2016 and 49.6% in 2015. It has been losing effectiveness since its peak in 2014. Using Pitch Info’s runs above average metric, we see Bumgarner’s four-seamer peaked in quality at 1.25 runs above average per 100 pitches in 2014 and has dropped each year since then: 0.97 in 2015, 0.39 in 2016, -0.35 in 2017 and -1.14 in 2018, a career low.


bum brooks.png

As seen in the Pitch Info Whiff Percentage charts above, Bumgarner’s four-seam fastball had its lowest whiff rate of our period of study in 2018 (seen on the left), likely leading to it’s ineffectiveness. Similarly, Bumgarner’s four-seam is measured to have had more vertical sink, independent of gravity, than it had throughout this period (seen on the right). Depending on the pitch, more movement generally increases whiff rates. A four-seam fastball moving more like a two-seamer, though, would lose swing-throughs: sinkers (two-seamers) generate more contact in the form of ground balls.

Screen Shot 2018-10-10 at 3.45.35 PM.png

Bumgarner produces his highest ground ball rate with his fastball since 2013, while generating the fewest whiffs with his fastball of his career. Couple the results with the change (increased vertical movement), and it appears his fastball began to behave like a two-seam fastball.

Statcast seems to have determined this already. According to Statcast, Bumgarner threw his four-seam fastball only once in 2018, as compared to 38.6% of the time in 2016 and 41.1% of the time in 2015. He replaced them mainly with two-seam fastballs, but also with some curveballs and changeups.


When comparing Statcast to Pitch Info, I wondered if Statcast could have been misclassifying four-seam fastballs as two-seamers. Through looking at the above plots, however, it’s clear a cluster of pitches was missing in 2018. The above graphs are of every pitch Bumgarner threw, by horizontal (x-axis) and vertical (y-axis) movement, colored by Statcast pitch classifications. Even when ignoring pitch type labels, a pitch type is seen to be missing. Specifically, Bumgarner’s high-rising, fairly straight pitch was missing. On a side note, notice how inconsistent 2017’s movements were: likely because Madison had to recover form a major shoulder injury, struggling with consistency.

With Statcast data, we can evaluate what happened with greater depth than through other methods. Below is a table of statistical changes in both Bumgarner’s two-seam and four-seam fastballs.

fastball stats

Velocity is measured in miles per hour, spin in revolutions per minute, extension is feet from the rubber, and horizontal and vertical movements are in inches from release point. Ignore 2017, as it was a very inconsistent year (as seen with the movement chart above). Both two-seam and four-seam fastballs in 2015 and 2016 had significant vertical rise due to spin. In 2018, however, Bumgarner couldn’t or wasn’t spinning his fastballs as much, resulting in less rise and more downward movement. This could be why Statcast is misclassifying his fastballs.

Why has Bumgarner lost spin on his fastballs? The data suggests two reasons why, both of which could be correlated. He’s lost velocity, and release speed correlates with spin rate. Similarly, Bumgarner has less extension on his fastballs than in 2016. His 2018 extension is similar to his 2015 extension, but because he’s lost velocity, the loss of extension could be penalizing. This loss of extension could explain the loss of spin if it’s related to grip or release.

Extension loss to home plate reduces the perceived velocity the batter anticipates, making it easier for the batter to time the pitch. Both loss of velocity and extension would combined greatly benefit the batter, at the expense of Bumgarner’s fastball.

What could have caused the loss of velocity and extension? Bumgarner is 29 years old, so there is a small chance he’s entered his decline. The likely culprit, though is injury: Bumgarner fell of a dirt bike in April 2017, injuring his left shoulder, and broke his left hand on a line drive comebacker in Spring Training 2018, requiring surgery. Being left-handed, both injuries could have significantly affected his 2018.

One year away from free agency, Bumgarner likely hopes he can recover lost velocity and spin on his fastball. Whether it was an organizational change or one driven by injury, his 2018 fastball difference was one to forget. His shoulder should be better healed, one year further removed from his accident, and hopefully his throwing hand does the same.


– tb


This post was featured on the FanGraphs Community Forum

The National League trade market – buyers, sellers and bubble teams

Halfway through June is approximately one-third of the way through the MLB season. It also happens to be about 60% of the way to the trade deadline. As we approach the trading season (which may have started already), we would like to know which teams may be selling and which may be buying. Specifically, which of the bubble teams, on the fringe of contending, will buy and which will sell?

I defined a bubble team, a fringe contender, as a team that was between 2 and 8 games back in the division or wild card. These teams are close enough to a playoff spot that, with the right 10-game stretch, they could be in line for the postseason. As the end of the season approaches, the upper bound on this range of contention will likely shrink. For now, with so much time left in the season, it allows us to analyze a large number of teams who could push for the playoffs.

The analysis will be broken up by league. I will also briefly mention non-bubble teams, though many of their plans should be obvious (I’m looking at you, Miami). The data used is through June 12th, collected on the morning of the 13th from Fangraphs (team statistics & rest-of-season schedules), Baseball Reference (team ages & division games back) and (wild card games back).

National League:

Non-Bubble Teams – Buyers:

Diamondbacks, Dodgers, Braves, Brewers, Cubs, Nationals.

As you could imagine, division leaders and those in close proximity are considered buyers. Whether to overcome that small deficit or to grow their lead, these teams should be looking to fortify any holes in their rosters. The willingness to buy, however, varies team-by-team.

The Braves, being young, should feel less urgency in action on this season’s trade market. They are the fifth-youngest in the National League in average batter age and seventh-youngest in average pitcher age. Similarly, their weakest link should be improved upon internally over the next few years. Their pitching staff has a collective 4.02 FIP, 12th in the National League, but they also have eight pitchers in their top-11 prospects.

The Brewers and Diamondbacks, both older teams, should be expected to buy heavily. Neither has a firm grasp on their division, and neither should expect youth infusions over the next few years to lengthen this contention window. Their farm systems are weak (albeit the Brewers are more middle of the pack), and their MLB rosters are old.

The Cubs, Dodgers and Nationals all have youth in their systems. Similarly, all three were projected to win their divisions, and all three aren’t (yet). The Cubs need help with their pitching, ranking 10th in the NL in staff FIP. The majority of their youth is on their MLB roster, as opposed to in the minors. The Dodgers have plenty of young depth in the minors but may need some major league starters should their use of the 10-day DL continue. They have youth on their roster and in the farm. The Nationals’ offense is struggling a little, but much of that is tied to their DL issues and Harper’s lack of contact (that should rebound). The farm has begun to produce (Juan Soto) and has more pieces ready to contribute. Overall, this group is in a good position to contend now and in the near future.

Non-Bubble Teams – Sellers:

Marlins, Reds.

What else is there to say about these teams? Having a sub-.400 winning percentage at this point in the season all but guarantees a spot in this section. Both teams are young and pursuing youth (except for the Reds, who enjoy watching Hamilton and Votto lose trade value as they age). One day, should their youthful prospects (like Brinson) bloom into quality major leaguers, these teams may contend.

Bubble Teams – Buyers:

Cardinals, Phillies.

To be honest, I expected more bubble teams to be clear buyers. With how many teams are treading water in the National League, hanging on the fringes of contention, I though many teams would be in position to buy. Upon investigation, however, these are the only two clear buying teams. Even calling these two teams ‘clear’ buyers may be overselling their situations.

The Phillies have the youngest bats and second-youngest pitchers in the National League, with a strong farm system backing. They should look to improve their batting: the Phillies have the fourth-worst wRC+ in the NL at an 88 wRC+. Because of their recent, erm, “reconstruction” (let’s just call it what it is – tanking), the Phillies have plenty of money to spend. Once they got out from under the contracts of yesteryear’s World Series team, they kept salaries low as they tried to take advantage of their draft positioning. As a team that has the capacity to spend up to $198 million, they have plenty of room above their current $92 million payroll to add contracts at the trade deadline. By taking on money, they can reduce the prospect cost of trades, preserving their future talent. One reason the Phillies may not be an aggressive buyer at the trade deadline, though, is the free agent market. Some top, young players will be free agents this offseason and the next, such as Manny Machado and Bryce Harper, and the Phillies have been rumored as willing to splurge.

The Cardinals have a youthful pitching staff but an aging lineup. Their pitchers are the fourth-youngest staff in the NL, but their bats are the sixth-oldest. Not only are their bats old, but they’re struggling – the Cardinals have a 94 wRC+, about middle of the pack in the National League. A few things suggest the Cardinals may not be aggressive in buying at the deadline. Historically, the Cardinals haven’t made many major mid-season acquisitions, opting to develop strong careers out of under-the-radar prospects, which reduces the need for outside help. The Cardinals have a good farm system, but may not quite have enough talent they’re willing to move to acquire a top bat without increasing payroll. This year’s payroll may restrict the Cardinals’ ability to add players, though – this season, they are operating under their second-largest payroll in club history.

Both the Phillies and the Cardinals should be shopping for a bat or two this July. The trade market should be flush with bats. Due to payroll and minor league system strength, the Phillies are more likely to make a significant acquisition. I expect both teams to be active in the rumor mill, but the Phillies to make a move.

Bubble Teams – Sellers:


How are the San Diego Padres, a team in the midst of a rebuild and a handful of games below .500, a bubble team? The NL West. Four teams have winning percentages below .515 (approximately two games above .500 at this point in the season), and the division leading Diamondbacks only recently broke free from those four teams (8-2 in their last 10). Despite being only 6.5 games out of a playoff spot (both the division and wild card), the Padres likely will be sellers.

The Padres have built an attractive farm system. They sacrificed a few years of competitiveness to both save money and acquire prospects (and Dave Cameron). Despite this, though, they have increased their payroll over the last five or six years. This year, they’re operating on a payroll of $102 million. The Padres took on bad contracts to receive better prospects in trades they’ve made. Because they are operating at a salary level close their recent maximum of $143 million (2017), the Padres likely don’t have the money to take on contracts and, because they’re still in their rebuild, would rather not trade away some of their future talent.

The Padres are likely to sell mainly because they aren’t in a position to contend and are still forward-looking, planning on future contention. With eight teams between them and the wild card, buying almost seems like a necessity in any push towards a playoff spot. The pursuit of talent will drive the Padres’ July.

Bubble Teams – It Depends:

Giants, Rockies, Pirates, Mets.

Each of these four teams may buy or sell, depending how the next few weeks go. All four teams are in similar positions – lacking in farm system depth, operating at their highest payroll levels (Giants, Rockies, Pirates, Mets) and, besides the Pirates, all are older. These teams’ contention windows are closing, and, unless things change, won’t be open for a while. Should they buy and push for one last postseason, or should they begin their rebuilds with midseason selloffs?

The San Francisco Giants are a difficult team to read. They are operating dangerously close to the luxury tax line and have money on the books for the next few years, preventing high-money acquisitions. They also lack the depth in the minor leagues to supplement trades to encourage their trade partners to eat money. The Giants’ batters are the oldest group of batters in the NL, and their pitchers are the tenth-oldest. Despite this, though, the Giants have acted like a team trying for one last push – they pursued Giancarlo Stanton during the winter and acquired both Andrew McCutchen and Evan Longoria (who has three years remaining on his current contract). Their remaining regular-season schedule is one of the easiest in the National League – their opponents project to have .494 winning percentage. Giants executive Brian Sabean said that “to be competitive to start the year and hopefully have to also roll into making some moves at the deadline,” they may have to make difficult decisions. Nothing in his statement suggests they will sell and rebuild.

The Colorado Rockies chose to pursue contention after reaching the playoffs for the first time since 2009. They signed multiple relievers and increased their payroll to its highest level in club history, $134 million estimated. If they are in contention at the deadline, they may continue this trend of spending – or they may have reached their maximum payroll. Despite playing in Colorado, their bats are the worst in the National League (when factoring in ballparks) with a wRC+ of 80. The Rockies need offense to contend. They don’t have room to take on contracts, nor do they have a strong farm system to utilize in trades. The Rockies front office has shown a willingness to spend (see the above comment on their offseason), and may want to push for contention during their prime years – while Blackmon is younger and Arenado still under their control.

By all accounts, the Pittsburgh Pirates are rebuilding. They moved Gerrit Cole and Andrew McCutchen during the offseason to save money, despite having the pieces to, on paper, appear in contention. Implied by the moves is that the Pirates were operating close to their maximum payroll – despite those moves, they’re running their highest payroll ever – and prioritized savings over spending and contending in their final year with Andrew McCutchen. They don’t have the farm system to draw on in trades, nor payroll to take on contracts. Most signals point towards the Pirates selling. Moves like the Dickerson acquisition, however, remind us that the Pirates aren’t trying to lose games and, in shrewd ways, will seek to win. Should an opportunity arise in which the Pirates can improve without increasing payroll or mortgaging the future, they may buy.

If the Mets’ ownership were willing to spend, they’d be buyers. At least, according to their fans – the Mets are running their largest payroll ever ($175 million) and have shown no indication that they plan to sell. They have the second-oldest group of batters and a weak farm system, though. Like most of these contending teams, the Mets need batters and, like most of these teams, don’t appear to have payroll or prospects to acquire them. Injuries have bitten the Mets as well, with their arguable top bat and arguable top pitcher both landing on the DL (Cespedes and Syndergaard). Unless the ownership is willing to cross the luxury tax threshold, the Mets likely will sell or stay put at the deadline. Their performance in the next few weeks may dictate whether they buy, which would be difficult, or sell.

All four of these teams have payroll and farm system limitations on their abilities to buy. Similarly, all four teams may not see contention for a while. Whether or not they should buy or sell likely will be determined by one of two things: their performances over the next few weeks and their ownership. If any of these teams hit a slump, or go on a hot streak, the decision to buy or sell becomes easier. If ownership or the front office realize future contention will be far away and one last push is worth it, they may buy regardless of what happens over the next few weeks.

Overall, the trade market in the National League seems murky. There are clear buyers, clear sellers, and quite a few unsure teams. The next few weeks should dictate whether these bubble teams buy or sell. Regardless of what they do, one thing is certain – the trade market will be active.

Note: Given the amount of time and research required to write this piece, I do not plan on writing an American League version. The amount of detail required to determine how teams should act is beyond what my schedule allows me to research and discuss. I left out quite a bit in this NL version (such as divisional strength over the next few years, etc.).


– tb

Can we fix Lewis Brinson?

Update (6/12/2018): It looks like he read my article! All kidding aside, Brinson had a great game June 11th, against Bumgarner and the Giants. I noticed he worked on two of the three things I suggested in this article – starting his leg kick earlier, and allowing his hands to move as he loads. Below is a gif of a triple he hit off of Bumgarner, where you can see both those changes in action (from He still opened his hips early, something his natural power and athleticism compensates for. That may be something inherent to his swing, or it may require an offseason to work on.

Back to the original post!  – tb



Lewis Brinson has underwhelmed during his time in the majors. Despite dominating AAA competition (wRC+’s of 163 and 146 across two stints), he has struggled to find his stroke against MLB pitching. As a highly-rated prospect, Brinson provided power, speed and defense in a unique combination in the minors – a desirable trilogy of skills. He has played closer to his floor than his ceiling, though, since debuting in the majors. Using both Fangraphs and Statcast data, obtained the morning of June 8th, as well as video, I sought out to try to find a fix for Lewis Brinson.

In Brinson’s initial cup of coffee, in 2017, he ran a rough 30 wRC+ and .225 wOBA in 55 PA with the Brewers, according to Fangraphs. After being traded to the Marlins, Brinson rode a solid spring training performance (.328/.365/.586) into a starting center field role, having appeared to turn a corner after 2017. Since the season began, though, Lewis Brinson began to perform like it was 2017 again. Through June 7th, he’s batting .168/.214/.313 with a 32.1% K-rate and a measly 4.1% BB-rate, good for a 41 wRC+, second-worst among qualified batters. His Fangraphs prospect tools, seen below, suggest he is much better than his current performance indicates.

brinson grades.png

Lewis Brinson was a top prospect in the minor leagues, peaking at 13th on and Fangraph‘s prospect rankings lists as some point within the last year. Brinson’s tools are promising. Essentially, he was seen as a power hitting speedster with a strong arm, average to above hands and fielding instincts, and a below to average contact ability. In the majors, Brinson has displayed above-average fielding and great to excellent speed – 29.5 ft/sec sprint speed, 8th at his position and 44th in the majors – but has yet to flash his game power and has mightily struggled with contact, to the point where it may be masking his power. When he makes contact, like in AAA, he displays uncanny offensive abilities: .343/.392/.575 with 17 home runs and 15 stolen bases in 433 PA, with a 19.2% K-rate and 7.9% BB-rate.

One of the major areas of concern for Lewis Brinson is his ability to make consistent contact. Specifically, he has had a hard time getting under the ball, too frequently hitting the top instead. As seen below, his Statcast data suggests he has a flat swing, as opposed to the slight uppercut many pros pursue. Brinson hits too many ground balls and topped balls, resulting in a low launch angle. Higher launch angles could help him utilize his natural power.

brinson batted balls.png

I felt Dexter Fowler was a decent comp to use for Lewis Brinson because of his similar body type and skill set. Brinson is 6’3″, 195lbs. and Fowler is 6’5″, 195 lbs. During the 2016-2017 seasons, Fowler displayed similar power and speed numbers to Brinson’s AAA performance. Given that similar power and speed profile, I chose to compare Fowler’s 2017 season’s launch angle distribution to Brinson’s. Below are both of those distributions – on the left, Lewis Brinson’s 2018 season and on the right, Fowler’s 2017.

brinson launch

Clearly, Dexter Fowler capitalized on productive launch angle zones. Ideal launch angles are between 10 and 20 for line drives and 20-30 for fly balls (wide estimates, but they paint the right picture). Lewis Brinson, however, struggles to find those optimal launch angles. His launch angle distribution reflects that – the majority of his batted balls are hit into the ground, at launch angles at which balls rarely becomes hits.

Given his 6’3″ 195 lb. frame, Brinson struggles to make contact with pitches low in the zone. Below is a Fangraphs heat map of contact rate per area of the strike zone. On the left is Lewis Brinson’s 2018 contact rate. On the right is Dexter Fowler’s right handed contact rate from 2016 and 2017.

brinson swings.png

Lewis Brinson clearly struggles with low pitches, especially on the corners. Compare that to a 2016-2017 right-handed -batting Dexter Fowler (who ran a 120 wRC+ with a .355 wOBA), and you see the difficulties Brinson has had with making contact. Part of this surely is because Brinson is a rookie and needs to acclimate to MLB pitching. The likely cause, though, is his swing, which we can break down over time.

Through browsing the video archives (translation: Google Search Engine), I came across three separate swings Lewis Brinson has deployed in recent years, with varying success. The first swing was from his 2016 AA stint with the Frisco Roughriders, while the other two are both from 2018 – April 21st and May 4th. The three clips I chose are of home runs, with two of them (AA and May 4th) having the pitch in the same location. For convenience, here are gifs of each swing.

2016 AA:


A few key details to notice. Brinson starts his leg kick before the pitch is released, . He also has a slight drop in his hands, a timing or loading mechanism for his swing. Also, from this perspective, we can’t see Brinson’s back knee until the moment he makes contact. We can see quite a bit of his jersey number, implying a strong turn and load.

2018 April 21st:


Here, Brinson is using a different leg kick. He lifts it prior to release, but earlier than in AA, and holds his leg in the air a bit. He’s removed the depth of his hand movement in loading, as well. Even though it is a different camera angle, it’s clear that Brinson’s back leg is exposing itself prior to contact. Not as much of his jersey number is exposed on his turn, though some of that could be camera angle differences.

2018 May 4th:


In his most recent swing, only a few weeks after the April 21st swing, Brinson has reduced the magnitude of his leg kick. He starts his kick as the ball is being released, but uses a few leg movements prior to the release as a timing mechanism. Similarly to the previous swing, Brinson has reduced the magnitude of his hand drop and exposes his back leg prior to impact. Despite an aiding camera angle, not much of his jersey number can be seen.

Upon first view, I felt like the 2018 swings lacked athleticism which, for such an athlete as Brinson, is suboptimal. It appears that his upper and lower bodies aren’t working as one – exposing his back leg prior to contact implies he is opening up too early, even if his hips don’t appear to do so. These swings can be viewed as a one-two swing, where his lower body fires and then upper body, in a one-two sequence. By removing his hand drop, Brinson may have thrown off his load timing. Whether this is affecting the timing of his leg kick, or if the timing of his kick is conscious, is unknown, but his leg kicks in 2018 also appear suboptimal. Neither the larger, hanging leg kick nor the on-release leg kick appear to help his timing. Brinson appears to lack a deep load – even with an off-center camera angle, not much of his back can be seen, implying his shoulders aren’t in a powerful location during his load.

Compare his 2018 swings to a 2017 Dexter Fowler home run swing. Despite it being a left-handed swing, differences are immediately apparent.


While Lewis Brinson is starting his current leg kick upon pitch release, Dexter Fowler is almost finishing his leg kick then. This allows Fowler to load into an athletic position, with his shoulders and hips turned, exposing most of his jersey number despite us having a camera angle that would hide his back. Fowler drops his hands upon loading, moving them back which supports his athletic load and turn. Despite starting in a slightly open position, Fowler doesn’t expose his back leg until impact or even slightly after. His upper and lower body work together, in sync as opposed to sequentially. Fowler’s swing here is explosive.

We can identify a few swing fixes we can suggest to Brinson, based on our swing breakdowns. The first would be his load mechanism – previously, he used his hand movements to load his swing into a turned, athletic position, while timing his swing with a small but effective leg kick. By trying to remove his hand motion, Brinson lost his deep load. Changing his leg kick led to a loss of timing, breaking the athletic chain and resistance his swing needs for coverage and power. These two changes broke the synchronization between his upper and lower body, which makes both contact and power more difficult to find. Brinson is very athletic – he likely has been relying on his athleticism more than his swing as of late.

How could these changes help Brinson? They could help put his swing in better positions to cover the lower part of the plate, and to cover the entire plate with greater efficiency. The quality of his contact could increase, as he gets his entire body working as a single, power-transferring unit. With better quality contact, he could get under the ball and square it up more, driving it along ideal launch angles and utilizing his natural power. Or, these changes could hurt him. As with many sports, fixes that may help some may not help others.Whatever Brinson is trying, though, doesn’t seem to be working.


– tb


This post has been published at Fangraphs! Woohoo!


April showers bring May flowers – Brandon Crawford’s changed approach.

Brandon Crawford has always been known as a defensive shortstop. His three-straight Gold Glove awards can attest to that, as do advanced metrics (he isn’t pulling a Derek Jeter). It wasn’t until Crawford’s third full season (2014) that he became an above-average bat. Though, with a 101 wRC+, he was more average than above. Thanks to a power surge in the following season (that may or may not have been aided by the juiced ball), Brandon had his offensive career-year, running a 113 wRC+ along with 21 home runs, 11 more than his previous career high.

Essentially, this is a long-winded way of saying Brandon Crawford hasn’t a middle-of-the-order, annual Silver Slugger-contending batter. The majority of his value is produced on the field. Because of this, Brandon Crawford’s 44 wRC+ from the start of the season through April 25th was concerning but not devastating. All the analysis in this piece was done using data from March 29th, 2018 through June 26th, 2018.

April 27th, 2018 may be remembered as the day the Giants’ shortstop energized their offense. According to Alex Pavlovic, Crawford made a mechanical adjustment in his swing. In his own words, Brandon is “getting [his] hands up and into the right slot by the time [he] start [his] swing.” Below are two set positions, immediately prior to the pitcher lifting his leading leg in his motion. Notice his hand positions.

crawford bats.png

On the left is an at bat against Alex Wood from March 30th, 2018, where he struck out and went 1-3. On the right is an at bat versus Brooks Pounders of the Rockies, on May 19th, 2018. He went 3-5 with 4 RBI’s that day. Both images were from videos found on MLB’s Youtube page.

Like Brandon said in Pavlovic’s piece, the change was only a few inches of hand relocation. Below I highlighted the hand & bat angle to help. Note: the camera angle is slightly tilted, contributing partially to the angle of his hands in the second image. Through viewing multiple swings, I can confirm the angle seen is close to or equals what he is currently doing.

crawford bats highlight.png

It may still be tough to see, but it’s there. This subtle change, contrary to the current ‘air ball‘ revolution’s lowering of ones hands for added loft, has fueled Brandon Crawford’s May. He had one of the hottest May’s of 2018, running a .448 wOBA and a 190 wRC+.

How has this mechanical change led to such a hot streak? Well, one could say he’s gotten lucky. Pitchers began to throw more pitches in the strike zone, of which Crawford is taking advantage. On the left is a heat map of pitches thrown to Brandon Crawford prior to the mechanical chance, and on the right is after the change. All the heat maps are from Fangraphs.

crawford pitches

Pitchers aren’t the only ones locating the outside corner more. Crawford has increased his plate coverage since raising his hands. Before the change, he was struggling to make contact anywhere besides on the inside corner. Now, however, he is covering both corners, and up in the zone. Like above, the left heat map is from the period prior to the change, and the right heat map is from after the change was made.

crawford contact.png


What does this look like statistically? Through Statcast, we are able to measure the changes in Crawford’s batted ball distribution and quality of contact. The data in this table and the below distribution are from Statcast, through Baseball Savant.


Brandon Crawford has hit the ball much harder since the hand position change, increasing his exit velocity by 6 mph! xwOBA, a stat that encompasses all offensive contributions and can be read like batting average, validates this improved batted ball profile. xwOBA uses a batter’s launch angle and exit velocity for each batted ball to calculate the expected wOBA value for each event, as an attempt to strip away defense and luck from the batter’s offensive performance. Brandon’s launch angle has lowered, however, furthering itself from the ideal fly ball range of the low to mid-20 degree range (though, some research may suggest that, at a 90 mph average exit velocity, a 13 degree launch angle may be optimal).

Average launch angle is deceiving, however, as extreme batted balls aren’t captured as well in the mean of all batted balls. A ground ball with a -10 degree launch angle and a pop up with a 45 degree launch angle would imply that the batter has an ideal launch angle of 17.5 degrees, though a ground ball and a pop up aren’t ideal outcomes. Below is Brandon Crawford’s launch angle distributions, before and after his hand position change.


If anything, Crawford has trimmed worse-balled balls in favor of ideal batted balls. Despite lowering his average launch angle, Brandon Crawford increased the frequency of high-performance batted balls, namely line drives. As seen in the post-change pink distribution, Brandon reduced the number of pop ups and extreme ground balls. This can be seen in his batted ball rate statistics. This data is from Fangraphs.


The changes in his offensive profile are reflected in the above table. Brandon’s increased line drive rate is seen in both the distribution and the rate statistics. His average launch angle decrease comes from replacing many fly balls with line drives. This high line drive rate helps explain the high BABIP (batting average on balls in play). Similarly, pulled balls are hit harder and, shift-dependent, can do more damage to the opposing team. Brandon’s K-rate decreased from dangerously high in one period to far below average in the post-change period, while his walk rate fell further below average between periods. Both of these drops were caused by the increased zone rate mentioned above (in the heat maps).

Brandon Crawford had a far-too high K-rate while being far too unproductive for his team. After receiving a bit of swing advice, raising his hands a few inches, he has become one of the hottest hitters in baseball. Through the high line drive rate and BABIP, we should expect this intense May to cool down at some point, though with the stronger plate coverage and better approach at the plate, Crawford shouldn’t return to his April self.


– tb


This post was accepted on Fangraphs’ Community Research blog! (and with updated stats)

How Sabathia reformed his career, and could keep it going

I love rooting for late career resurgences. Seeing a player with diminished skills, who likely considered retirement, turn their career around for a few more years instills a feeling of hope. From an analytics perspective, how the player resurrects his career is fascinating.

A few years ago, a season after undergoing arthroscopic debridement surgery, CC Sabathia changed his style of pitching. He found a cutter. In 2016, CC began to ditch his four-seam fastball and replace it with a cutter. He learned his cutter from former teammates that may have had decent careers: Mariani Rivera and Andy Pettitte, one of whom is very likely a first ballot hall-of-famer largely because of this pitch. Sabathia’s cutter drove the resurrection of his career.

Note: The pitch type data is from Pitch Info, hosted on Fangraphs. Performance data is also from Fangraphs. Tunneling information is from Baseball Prospectus, through May 12th, 2018.


CC Sabathia has been changing his pitch distribution quite a bit over the last five-plus seasons. The change that revitalized his career, though, came during the 2015 offseason. His four-seam fastball usage dropped from 28.3% to almost nothing at 2%, while his cutter usage increased from 0.6% to 31.6%. Since 2016, CC has increased his slider and cutter usage while decreased his sinker and change up usage.


Statistical Summaries: ERA- and FIP- measure ERA and FIP, compare them to the league average, and normalize them to 100. An ERA- of 51, for example, is extremely good – it means CC Sabathia has an ERA 49% below league average. wOBA, or weighted On Base Average, is a batting average-like measure that combines a batter’s overall offensive contribution. R wOBA is wOBA from right handed batters against CC Sabathia, and (R-L) wOBA is the difference between righty and lefty wOBA against.

As CC’s cutter usage has increased, his performance has as well. Relative to league-average, his ERA and FIP have dropped annually since implementing a cutter. Each season he has used a cutter, CC has been above-average. I included innings pitched to indicate his surgical leave in 2014.

Most of this improvement has been driven by CC’s performance against right-handed batters. Righties had a .347 wOBA in 2013 and .370 wOBA in 2015 against Sabathia, both at least 54 points above lefty wOBA against him. Since adding a cutter, CC has lowered right handed batter wOBA against from .316 to .310 and now .278, with the largest gap between lefty and righty wOBA being 26 points.

Replacing a four seam fastball with a cutter has its benefits. A cutter runs in on the hands of a righty, inducing weak contact. It deceives batters, appearing as a fastball yet cuts glove side instead of running arm side. And for CC Sabathia, it tunnels well with his secondary pitches.

Pitch tunneling, in a basic sense, occurs when two pitches appear similar at the ‘point of no return,’ where the batter decides whether or not to swing. By the time a batter realizes he should or shouldn’t have swung, the second pitch would ideally be far from what he expected.

Below are two examples of pitch tunneling. These pitches were from at bats between Sabathia and Randal Grichuk early in 2018. CC tried to use his slider to set up the cutter. The dashed black lines are the pitch trajectories. The flags are the pitch destinations, while the smaller flags on the trajectories are pitch locations at Grichuk’s swing decision point.


The pitch sequence on the left was tunneled well. The two pitches are almost indistinguishable at the batter’s decision point. The sequence on the right, however, were poorly tunneled. It’s clear that the pitches thrown were different types and in different locations.

Statistical summaries: PreMax measures the average distance, in inches, apart the two tunneled pitches are at the batters’ decision point. The average PreMax is said to be about 1.54 inches. PlatePreRatio measures the ratio between the average perceived distance and average actual distance between the tunneled pitches at the plate. The perceived distance is the distance the batter expects will be between the pitches when they reach the plate. The median PlatePreRatio in 2018 is 11.8. This ratio represents how many times further the pitches are apart than expected. For example, the average pitch tunnel sequence results in pitches being 11.8 times further apart than expected.


CC Sabathia has improved his PlatePreRatios through replacing his four seam fastball with a cutter. He also has improved his tunneling skills with his cutter over time, as he has gotten more comfortable using it and as he has gotten further from his surgery. CC’s tunneled pitches are much further apart at the plate than expected when he leads with a cutter instead of a four seamer. The current assumed average PreMax is 1.54 inches, of which Sabathia is above with his cutter, though over time he is improving. Quite a bit of research is needed to better understand pitch tunnels, but it is generally assumed that tunnels with higher PlatePreRatios, all else being equal (pitch types, movement, location, PreMax), are harder to hit and are more successful.

One thing to note, though, is that not everything improved for Sabathia in regards to pitch tunnels. PreMax, in my opinion, is very important for pitch tunnels – perhaps mores than PlatePreRatio. Regardless of how far apart two pitches end up compared to their expected destinations, if the pitches can be clearly identified prior to the swing decision time, the batter can make a much more educated decision. Ideally, a batter decides whether or not to swing purely based on the perceived location and his opinion of whether or not he can make quality contact. Pitches with smaller PreMax measures appear more similarly and can deceive the batter. Pitches with higher PreMax measures provide the batters with more information – whether it be pitch type (which could influence a batter to not swing if he knows he struggles against it) or a variable like pitch location, which lowers the PlatePreRatio through providing a more accurate perceived distance.

All three of Sabathia’s commonly-used pitch tunnels, listed above, became more differentiable when the cutter replaced CC’s four seam. More research is needed to understand if this is actually bad, like I theorize, or if the PlatePreRatio increase is enough to offset any of the hypothesized issues with higher PreMax tunnels.

If Sabathia asked me for help (which is shiny 51 ERA- in 2018 suggests he doesn’t need), I would recommend that he begin to pitch backwards more often. See the table below:


Pitching backwards is when a pitcher uses his secondary pitches initially instead of their speedier offerings. The above table compares CC Sabathia’s tunneling sequences when his cutter is the first pitch to when his cutter is the second pitch. Each of his cutter-second tunnel sequences has better PreMax distances and better PlatePreRatios than his cutter-first sequences. As mentioned above, the average PreMax distance is 1.54 inches, of which Sabathia is below on two of his three secondary-cutter sequences. When leading with the cutter, all three of his sequences are further apart than average. Similarly, Sabathia’s sequences have a higher PlatePreRatio when leading with the secondary than when leading with the cutter.

CC Sabathia had to transform his game to adapt to his diminishing velocity. He’s excelled at this, utilizing the cutter instead of the four seam fastball. Despite his changed approach and success, there are ways he could improve, such as pitching backwards with tunnels. He plans to retire if the Yankees win the World Series, though. He’s had a storied career, and may be HOF bound.


– tb


This post got accepted for Fangraphs’ Community Research blog!

The Astros & a full count.

Pitchers can sometimes be predictable. Across large samples, they tend to act similarly. Pitchers aren’t good hitters. Pitchers throw strikes on 3-0 counts. Pitchers use fastballs more than half the time*. You get the idea.

* individuals may not follow this, but the aggregate does. See Corbin, Patrick. 

Following this logic, one would expect pitchers in full counts to behave similarly. Because we have now entered the Statcast Era of Baseball, we can check to see if this expectation is valid! Using Opening Day 2015 through May 7th 2018 Statcast data (obtained the morning of May 8th), I explored how pitchers approach full counts. Below is the average pitch location, from the catcher’s perspective, for each team in each season 2015 through 2018 in full counts. One point stands out.


The 2018 Houston Astros are doing something we haven’t seen before on full counts. They’re favoring a corner! For perspective, the 2018 Astros average full count pitches that are slightly over 6 inches away from the center of the zone. The next furthest average full count pitch is the 2018 New York Yankees, a full 2 inches closer to the center. Note: I assumed zone dimensions of 17 inches wide by 24 inches tall, centered on (0, 2.5). Please correct me if you have research or sources that vary, though regardless, the Astros are a clear outlier.

I won’t say much about the other outlier (immediately above the 2018 Astros) besides that it is the 2018 Los Angeles Angels. They’re throwing full count pitches, on average, just as far to the left batter’s box as the Astros, but at a close to average height.

For the rest of this analysis, I am going to solely look at 2018 data. Year to year strategies can change, so comparing the 2015 Giants to the 2018 Astros could be comparing apples to oranges – possible, yet inefficient.


The Houston Astros appear to have a concentrated plan to throw full-count pitches in the lower right portion of the strike zone. The above heat maps demonstrate an intentional focus down and on the left-handed batter box corner of the strike zone, as compared to the other 29 MLB teams’ full count pitch locations. Included in these heat maps is a strike zone overlay, using the above mentioned dimensions.

Perhaps the Astros utilize different full count pitch types. As seen below, there are a few differences in Astros pitch selection and rest of league pitch usages in full counts in 2018.


The Astros throw many more knuckle curveballs, a little more two seam fastballs and fewer changeups than the rest of the league. When combining standard curveballs and knuckle curves, the Astros still have a larger curve usage in full counts, though slightly smaller than the knuckle curve portion of the graph suggests. ThTwo-seam fastballs thrown, for example, on the edge of the plate would leak into the zone. This may be one strategy employed by the Astros pitchers.

Using Gameday’s Strikezone zoning, we can see this approach. Below is a table with the percentage of pitches thrown in zones 9 and 14, two zones down and away (from a right handed bater’s perspective). By looking at these zones, we see that Houston has thrown 32% of all their full count pitches low and on the right side of the plate, by far the most of all teams.



The Astros are, by percentage, on an island alone. Houston leads the Angels (the second outlier from above!) by a full 5.4 percentage points. They are almost triple the Rays in pitches to these zones, who are unique in their own right with such a low percentage of pitches low and away (from a right handed perspective).

Does this approach work? The Astros have the lowest launch angle of all teams on full counts, but the fifth-highest exit velocity. Their xwOBA is 10th in the league, at .373 (the Padres have a .305 xwOBA, almost 20 points lower than the second-place Giants). Houston does have the fourth-lowest wOBA at .356, despite their higher xwOBA. Only 8 teams have a wOBA higher than their xwOBA on full counts, which may be due to sample size (or could be due to some inherent quality of full count at bats). Without knowing how the Astros’ pitching would perform under general MLB strategies, we can’t confidently say this strategy works or doesn’t. Comparing it to other teams, though, suggests

We are dealing with somewhat small sample sizes, though, so these percentages can swing. This would be a very interesting topic to return to after the season. Despite the sample size and lack of measurable results, this was fun. Extreme abnormalities are always fascinating!


– tb