Chamberlain’s Stuff as a Starter

Yesterday, while doing a question-and-answer session with WFAN, Yankees general manager Brian Cashman was asked about Joba Chamberlain’s role with the Yankees. Chamberlain has bounced back and forth between the pen and rotation several times, but spent all last year in the pen. Now with the Rafael Soriano signing and questionable back-of-the-rotation options (which Paul Swydan outlined earlier) many have wondered whether Chamberalin would start next year.

But Cashman said the Yankees view him solely as a reliever. “I don’t think his stuff is the same since he hurt himself in Texas [August 4th 2008] … The stuff plays up better in the pen.” Cashman continued, “His stuff doesn’t play out of the rotation anymore like it did before prior to his shoulder.”

In 2008, Chamberlain started 12 games (65.1 innings), but then injured his shoulder and spent the rest of the season coming out of the pen. In 2009, the Yankees moved him back to the rotation and he started 32 games (157.1 innings). Comparing just time as a starter there is a stark difference between the two years: 10.2 K/9 in 2008 versus 7.6 in 2009, 3.4 BB/9 versus 4.3, 48% ground-ball percentage compared to 43% and, overall, a 3.42 xFIP versus 4.56.

And, as Cashman noted, the stuff is worse. His fastball lost 2.5 mph, again just comparing time as a starter in 2008 to 2009, and went from 6% swinging strikes per pitch to just 3%. And his slider dropped from 25% to 20% swinging strikes per pitch. Obviously 65 innings is a small sample, so some of the difference might have just been luck in 2008, but still it seems clear he was a different starter in 2009.

But his stuff is also worse out of the pen, comparing pre- and post-injury. His fastball is 2 mph slower and gets slightly fewer swinging strikes (5% versus 6%), and his slider also gets fewer swinging strikes (22% versus 32%). So the loss of stuff is across the board, not just when Chamberalin starts. And plus it is not hard to see Chamberlain more valuable to the Yankees as a back-of-the-rotation starter than a middle-innings reliever (Mariano Rivera, Soriano and David Robertson will be ahead of him on the depth chart). This might be particularly true if he had some more time to develop his change up.

But it looks like the Yankees are wedded to him as a reliever. And I guess I trust Cashman and the Yankees here. They have more information than we do on Chamberlain’s health, temperament and stuff, and how those play as a reliever versus as a starter.