A Baseball Weblog

Monday, November 29, 2010

What's different about Joba Chamberlain's slider?

Throughout Joba Chamberlain's major league career, his signature pitch has been his slider.  When he burst on the scene in 2007, it was virtually untouchable.  In 2008, it was an elite pitch again.  However, over the past two years, the pitch has appeared (according to my eyes, watching the games on television) to lose something - it just doesn't seem like he's fooling batters like he used to.  I did some PITCHf/x-digging on the slider, and I noticed an evolution in terms of the pitch's plate location, movement, and velocity. While by objective measures it is still a well above-average pitch, it has become increasingly easier to hit over the past three seasons.

First, though, I would like to examine the three years of Chamberlain's slider with a few metrics that tell us different things.  The first and, in my opinion, most important one is whiff rate.  Whiff rate, calculated by dividing swinging strikes by total swings, is good to look at for a pitch like Chamberlain's slider because he uses it in strikeout situations for a swing-and-miss.  Chase rate is also very telling as it shows the percentage of pitches out of the strikezone that batters swung at, and getting batters to swing out of the zone (and miss) is the goal of Chamberlain's slider.  The third number I'm presenting in the table below is zone rate, which is simply the percentage of pitches that were in the strikezone.  For the slider, it's better for it to be out of the strikezone, but only if it generates swings out of batters.  So, I think it's good to look at all three statistics together.

Year#Whiff RateChase RateZone Rate
While the chase rate has only declined a bit, the whiff and zone rates tell us that something's going on.  The whiff rate is still very good, but it is no longer exceptional like it was in 2008.  The pitch has found the zone a lot more over the past two years than it did in 2008, which is not a good sign.  What's causing the declining whiff rate?  The following distribution shows the normalized plate locations of Chamberlain's slider from 2008, 2009, and 2010.  The lines have been (somewhat) smoothed to better accentuate the trends.

As you can see, the distribution peaks slightly higher each year, showing that Chamberlain has located his slider slightly higher in the strike zone each year.  
This next distribution shows the vertical spin deflection (break) of Chamberlain's slider from the past three years.  A value of 0 represents a theoretical spinless pitch; the typical, league-average slider has about 2 inches of vertical spin deflection.    
This distribution also peaks higher each year, which means that Chamberlain has lost "drop" on his slider since 2008.  It's important to note, however, that PITCHf/x camera calibrations different from park to park and from game to game, so it's impossible to put utmost confidence into raw readings - though the samples are probably significant enough over a whole season, which is what we're dealing with here.  I also looked at the break of the slider on a game level in order to try to get more information about when his slider started breaking less.  Because of the park effects I mentioned, I chose to display the break of the slider in comparison to his average four-seam fastball break for that game (you could run into trouble if the movement of his fastball had changed, but it appears to move similarly to how it did in 2008).  The chart displays available data from all regular season games since April 1st, 2008.  

I identified a point where the slider appeared to begin losing its break, and I have separated the games before and after this into two clusters; it looks like something begins to change on September 4th, 2009 against the Blue Jays.  This was the second game of the "short start" experiment, in which the Yankees kept Chamberlain to a low pitch count in his starts in order to cap his innings.  (If you were wondering, that crazy outlier at the bottom is a May 3rd, 2010 game against the Orioles at Yankee Stadium in which the calibration was really odd.)  The trend continued in 2010, though the slider wasn't consistently as "short" as it was in September of '09.    

How about velocity?  The distribution below would indicate that Chamberlain was throwing his slider at an entirely different speed in 2010 than he was previously:

And by individual games?

The slider gradually gained speed relative to the fastball throughout 2008 and 2009 and leveled on the September 4th game.  Just to get some more confirmation on the break and velocity of the slider, I've plotted pfx_z difference versus velocity difference by game, and the correlation seems significant:

We can only speculate as to what the cause may have been - did he start "overthrowing" in September of '09 because he only had a few innings to pitch?  Then why would he continue overthrowing in the bullpen in 2010 when he wasn't in 2008?  Is it a mechanical glitch?  Is a physical problem causing him to lose command of his slider?  Clearly, I'm filled with more questions than answers on this front.  (You can help me become even more filled with questions in the comments section.)    

I'd like to examine one more thing in this post.  In the first paragraph, I mentioned that Chamberlain's slider is still a quality pitch by objective measures; my favorite way to gauge overall effectiveness of a pitch is by using run values.  In addition to standard linear weights (similar to the values on Fangraphs), I also like to look at defense-independent weights, with league-average batted-ball values substituted for actual events.  As you can see, the slider has been effective by both measures (lower numbers are better for pitchers):


So, just a few concluding thoughts.  My suspicions (which I first detailed twice after the 2009 season) were correct, on some level.  The slider has both lost break and gained velocity, and the change has been particularly noticeable since September 2009.  There was a higher percentage of hanging sliders in 2009 and 2010 than there was in 2008.  The difference may appear slight, but as the saying goes, baseball is a game of inches.  All in all, while the slider may not be filthy as it was in the old days, it's still pretty great.    

Sunday, November 28, 2010

Graph: Joba Chamberlain's velocity since 2008

This week, I've been working on a piece for Beyond the Box Score about Joba Chamberlain's slider.  As I was organizing pitch data by game, it was very noticeable that his velocity has fluctuated quite a bit over the past three years (yeah, like anybody ever talks about Joba Chamberlain's velocity ...).  So, here are game averages for Joba's four-seamer and slider, going back to April 1st, 2008.

The first noticeable dip is near the end of 2008; that was following his shoulder injury in August.  In 2009, when he was a starter, he was down about 3 mph on average from 2008 and usually sat at around 92 mph.  In 2010, he gradually regained his velocity and was consistently in the mid-90s.  (In case you were wondering, those outliers up at the top in 2010 are from some August games at Kauffman Stadium and U.S. Cellular field where the gun is hot.)  It looks like he's more or less back to where he was in 2008; he threw harder in 2007, but there is limited data from that year and I'm skeptical of its accuracy. 

I'll have another (much longer) post on Chamberlain up here tomorrow and on BtB Tuesday.  

Saturday, November 27, 2010

THAT Brian Anderson?

Per Ken Rosenthal, the Yankees have signed pitcher Brian Anderson to a minor league contract.  As I read this, I thought to myself, "Brian Anderson .... the name sounds familiar ... but who is he?"  Turns out, it's the same Brian Anderson who put up -0.1 WAR as a position player for the White Sox and Red Sox from 2005-2009.  The same one that made this awesome catch to send the White Sox into the playoffs in 2008.  But ... PITCHER?  What's this about?  I had been unaware of the fact that Anderson converted to pitching during the 2010 season while with Kansas City's Triple A affiliate after not making the club as an outfielder.  And apparently, he's got pretty good stuff.  According to Royals' manager Ned Yost, he's got a major league arm.  He's hit 97 mph, and his "comfort zone is at 95."  2011 bullpen possibility? 

Friday, November 26, 2010

Diamondbacks get Duke

On Thursday, the Pirates traded Zach Duke to the Diamondbacks for a player to be named, five days after designating him for assignment.  Duke had a tough year, sporting a 5.72 ERA to go along with 15 losses - his ERA was second worst in the majors behind Scott Kazmir (among pitchers with a minimum of 150 innings).  However, his BABIP of .347 was second highest behind James Shields, and his HR/FB% of 13.7% was third behind Javier Vazquez and Shields, so it's probably unfair to assume that he'd allow that many runs in 2011.  His walks were up a bit this year (2.89 BB/9 in 2010, up from 2.07 in 2009 and 2.45 for his career), as were his strikeouts (5.43 in 2010 versus 4.48 in 2009 and 4.71 career). What might Duke provide for his new team in 2011?  The three charts below simply give a run-down on his stuff, showing pitch movement (both full and aggregated; values are in inches) and velocity distribution. 

Duke has the typical five pitches - a four-seam fastball, a two-seam fastball that he uses more frequently than the four-seamer, a curveball, a changeup, and a slider.  He doesn't have a whole lot of velocity, as his fastball doesn't usually get out of the 80s.  None of his pitches appeared to be particularly effective in 2010 (use this as your glossary for now, and this as a refresher on run values):

#%Swing RateWhiff RateZone RateChase RateWatch RateRV/100xRV/100


GB RateFB RateLD RatePU Rate


He won't miss many bats, and while his control is good, it's not good enough to make up for his low strikeout totals.  The two-seamer and changeup are on the ground a lot, and overall he's above-average at getting grounders; that's a good trait to have at Chase Field.  He doesn't have the most exciting profile, but he's certainly not as bad as he was last year and could provide stability in the middle of the Diamondbacks' rotation.

Thursday, November 18, 2010

King Felix's 2010

Now that Felix Hernandez has officially been named the American League's Cy Young Award Winner, I can go ahead and publish this post that I've been working on for the last few days.


It's no secret that Felix posted excellent numbers (aside from his win total) in 2010.  He was second in innings pitched behind Roy Halladay, first in ERA, 9th in FIP, and 7th in xFIP.  His contributions earned him 6.2 WAR according to Fangraphs, which is good for sixth best in the majors and third in the league, behind Cliff Lee and the underrated Justin Verlander.  Using PITCHf/x, I've taken a closer look at Felix's 2010 season.

The King went with a five-pitch arsenal this year - a two-seam fastball, a four-seam fastball, a changeup, a curveball, and a slider (in order of pitch frequency).  The graphic below shows three different things: a chart of each pitch's spin deflection, a chart of the aggregated spin deflection for each pitch, and the velocity distribution for each pitch.  (DISCLAIMER!  Safeco Field looked to have some funky calibration issues for a lot of the season, making it difficult (more difficult than usual) to distinguish between four-seamers and two-seamers.  For the same reason, take the pitch movement data with a grain of salt.)  


As you can see, that's a hard changeup - he's thrown a few as hard as 93 mph this year.  (By the way, it does kind of defeat the purpose of the changeup if it's only a few mph off of the fastball.  I call it a changeup because Felix uses a changeup grip, but it acts more like a typical splitter.)  Hard curveball, too.  8 inches of vertical drop is substantial for an 82 mph pitch (though the data's probably skewed slightly by the Safeco calibration errors).  
Alright, so his stuff LOOKS impressive - but what kinds of results did his pitches get?  

#%Swing RateWhiff RateZone RateChase RateWatch RateRV/100xRV/100 


GB RateFB RateLD RatePU Rate


Well, it looks like we have some confirmation as to the nastiness of Hernandez's pitches, particularly his three off-speed deliveries.  Every one of his five pitches registers above average both in terms of actual run values and expected run values - that's five "plus-pitches."  The changeup is primarily used to get hitters to swing out of the zone, and curveball is swung at very infrequently (including pitches in the zone, which leads to the high watch rate).  The groundball rates, particularly for the change and curve, are filthy.  Also filthy are the whiff rates on the off-speed pitches.  It's impressive to have one pitch near a 40% whiff rate, let alone three.  Comparing them to the league average rates calculated by Harry Pavlidis earlier this year, here's what you get (with 100 as average, a la OPS+):

CH: 129
CU: 153
SL: 113
That gives Felix a lot of different options for a put-away pitch.  Which leads me into my next question: when in the count did Felix like to throw each pitch?  For this next chart, I will steal a graphical idea from Jeremy Greenhouse.  The columns represent pitches against all batters, and the tables are split by batter handedness.    

vs LHBFirstAheadBehindFull

vs RHBFirstAheadBehindFull

Generally speaking, Felix is most likely to go to the curve as his offspeed pitch with one strike and the change with two strikes.  Also of note is that with two strikes, the four-seamers greatly outnumber the two-seamers.    

So, hopefully this gives you a pretty good summary of how the King goes about his work.  To summarize:
1.  He's got velocity and movement on the fastball.
2.  He has three elite put-away pitches.
3.  He'll probably go to the changeup with two strikes, but it would probably work out fine if he used the curveball or slider. 

Oh, right; I almost forgot to mention that he's not even 25 yet.  Batters: beware. 

Pitcher pace added to Fangraphs

David Appelman just added pitcher pace to Fangraphs' PITCHf/x stats, and it looks like my post was his inspiration.  Awesome!  

Wednesday, November 17, 2010

Benoit heads for Detroit

Earlier today, Joaquin Benoit signed a 3-year deal worth $16.5 million with the Detroit Tigers.  Before I say more about the deal itself, I'd like to briefly recap Benoit's extremely successful 2010 season.  After missing all of 2009 with a shoulder injury, Benoit served as Rafael Soriano's primary setup man in the Rays' bullpen and compiled a 1.34 ERA in 60 1/3 innings.  He backed it up with strikeout and walk rates of 11.2 and 1.6 per 9, respectively.  He was undeniably one of the game's most dominant relievers while pitching in the toughest division.  He worked with a fastball that averaged 94 mph, a changeup at about 83, and a slider near 86.  The fastball and the changeup in particular were devastating last year:

#%Swing RateWhiff RateZone RateChase Rate Watch Rate RV/100xRV/100


According to my calculations, Benoit led the league in RV/100.  Theoretically, this would mean that over the course of 100 pitches, Benoit would allow 2.78 fewer runs than the average major leaguer (runs allowed per 100 pitches in 2010 was around 3).  My run values were implemented earlier in the year and don't reflect the depressed 2010 run environment, so use these numbers as a much more of a general guideline until I can update them.  Also, Benoit was the only pitcher to break -2 in terms of xRV/100, which is the defense-independent variant of the run values and is uses batted ball types substituted for actual outcomes.  Billy Wagner was the closest behind.

As for the contract that the Tigers just doled out to him, I don't think it's wise at all.  Clearly, Benoit was superb in 2010, but handing out a three year contract to a reliever is crazy risky, especially for someone with Benoit's injury history.  For what it's worth, Benoit's contract is the largest for a non-closing reliever in three years, since Scott Linebrink signed a contract with the White Sox for four years and $19 million, according to MLB Trade Rumors.  "Non-closing reliever" ... should Benoit be given a shot at taking Jose Valverde's job?  That's for another time, but my short answer is "yes."  Despite Valverde's incumbency, the Tigers should not hesitate to instill Benoit as the closer if Valverde struggles, because if he can perform anywhere close to his 2010 numbers, Benoit is the better pitcher.  

Monday, November 15, 2010

Neftali Feliz PITCHf/x

Just a quick PITCHf/x review of your 2010 AL Rookie of the Year.  The three graphs below show the spin deflection (from the catcher's perspective) for Feliz pitches, both the full scatterplot and aggregated values, and the velocity distribution for the pitches.  (click to enlarge) 

#%Swing RateWhiff RateZone RateChase RateWatch RateRV/100xRV/100


Spectacular fastball (it says four-seamer here, but there may be some two-seamers thrown in as well).  The slurve isn't bad, either.
Congratulations to Neftali!