Wednesday, December 12, 2012

2012 Statistical Trends: Joba's Comeback

(Courtesy of Getty Images)

2012 was a rough year for Joba Chamberlain.  After being shut down in 2011 and undergoing Tommy John Surgery, he was in the process of working himself back to full strength to make a summer 2012 return when he suffered his now infamous trampoline accident that resulted in a dislocated ankle.  When reports first came out on that injury, it sounded potentially career-threatening, but follow-up examinations and surgery made it much less so and Joba was able to return to a Major League mound in August.  Joba pitched to a 4.35/4.01/3.55 slash line in 20.2 innings pitched this past season, a small sample size to be sure.  But within that small sample size there are some interesting splits and trends that could point to a very strong 2013 campaign for Joba.

The first thing worth mentioning is Joba's velocity, simply because it's always been looked at as a barometer for how well he's pitching and it's more important to Joba's success than say D-Rob's or Mo's because he doesn't throw a fastball with movement like theirs.  Joba's velocity was also creating buzz when he made his 7 prehab appearances in the Minors, regularly sitting in the mid-90s and hitting 97-98 on more than one occasion.  There was talk that the "old Joba" was going to be back, and while that didn't come to total fruitition, his velocity was a positive in his 20.2 Major League innings.

PITCHf/x had Joba's fastball at 94.7 MPH, the fastest it's registered since '08, and also had his slider (87.0 MPH) and curveball (80.7) at the fastet they've ever been.  According to Texas Leaguers, there was an uptick in velocity in both the fastball and slider from August to September as Joba got more work and less rest between starts, a sign that he was healthy and had his stuff intact.  As a power relief pitcher who had watched his velocity slip since his debut, and who had worked through problems with various injuries and role changes, it was reassuring to see that this latest serious injury hadn't sapped Joba of any more of his stuff.  Because let's be honest, the guy still has plus stuff when he's commanding it.

And as it is with any pitcher who tip-toes on the line between average and good, and good and great, command was the name of the game for Joba in 2012.  It's common knowledge that command is the last thing a pitcher finds when he's coming back from TJS and Joba was no exception to the rule.  He pitched to an 8.59/7.73 slash in August after making his return, with just 6.14 K/9 and 4.91 BB/9.  Joba got beat up on his fastball, which he couldn't locate consistently within the strike zone.  Despite throwing it 77 times that month, more than any of his other offerings, Joba registered just a 1.4% whiff rate on the pitch.  If hitters are making contact with your fastball all the time, eventually they're going to square it up and put it in play.  And the more balls they put in play, the more hits they're going to get.  It also didn't help that Joba didn't quite have the bite to his slider that he usually does:

You can see the general path of the pitch's movement reflected in that plot, but the problem is there are way too many sliders catching the strike zone.  73.2% of Joba's sliders thrown in August were strikes, which is too high a rate for a pitch typically thrown as a swing-and-miss out pitch with 2 strikes.  Joba did get a 23.2% whiff rate on the 56 sliders he threw in August, but it was the inconsistency with his location and catching too much of the strike zone with the pitch that hurt him.  And it was the improvement on those problems with the slider that keyed Joba's turnaround in September.

That's Joba's slider plot from September through the end of the regular season.  It has the same general pitch location distribution as in August, but it's almost as if August's plot was shifted down and to the right, a sign that Joba commanded the slider better in September and threw it where he wanted.  There are more pitches on or near the lower corners of the strike zone and more pitches falling out of the strike zone that resulted in swings and misses.  Joba threw his slider 39.5% of the time in the final 5 weeks of the season, and despite registering a swing rate lower than what he did in August he registered a 31.6% whiff rate.  For the sake of comparison, David Robertson's curveball had a 19.8% whiff rate in 2012.  So Joba's slider in September was a big time out pitch.

Not surprisingly, Joba's fastball location also improved in the final month of the regular season, and with the help of that nasty slider combined to drastically change the rest of his peripherals for the better.  After a dreadful 7.1 innings in August, Joba pitched 13.1 more in September/October and posted a 2.03 ERA/1.97 FIP, 11.48 K/9, and 1.35 BB/9.  His velocity trended up, his command of his pitches trended up, and Joba's overall performance and appearance on the mound in the season's final month did bring back memories of his 2007 debut.

Looking forward to next season, it's difficult to draw conclusions or make predictions with as much confidence as I did when looking at Robbie Cano or Ivan Nova's 2012 trends based on the much smaller sample size.  But knowing what we know about pitchers coming back from TJS, and seeing how Joba trended in his 2 short months of work, there is reason to be optimistic and even excited about what 2013 could hold for him.  He had to work himself back into the best shape he's been in in years to get back on the mound this season, and did it while putting far less mileage on his arm because of the injury.

If Joba stays in shape in the offseason he should come into spring camp well rested and ready to go, and can spend more time focusing on his pitches rather than his conditioning to prepare himself for the season.  With Soriano gone, Joba moves up a rung on the bullpen ladder behind Mo next year, and if he can pick up where he left off at the end of 2012 the Yankee bullpen might not even miss old Sour Puss.

(All pitch charts and percentages courtesy of Texas Leaguers)

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