What's wrong with CC Sabathia?

Since joining the Yankees in 2009 no member of the team has been more consistent than CC Sabathia. The big guy joined the team and earned his paycheck from day one. Last season was a bit of a hiccup, but that criticism was overblown. Sabathia's FIP was 3.33 in 2012, better than what he managed in 2009 or 2010. The only real weakness in his season was that the previously durable Sabathia spent time on the disabled list. 2013 has been a different story. Any criticism of CC is justified. His slash line is 4.66/4.26/3.69. That is pretty much his worst season in the big leagues. Entering Sunday's game he's posted an fWAR of 1.8, leaving him on pace for about 2.4 for the entire season, also his worst ever. No matter how you slice it, Sabathia is having a down year. Why?

The biggest culprit is that he's giving up more homers. Prior to this season the most homers per game CC gave up since joining the Yankees was 0.76 in 2010. This year he's practically doubled that. He's allowing 1.41 homers per game. His strikeouts are down and his walks are up, but at 7.59 and 2.39 per nine innings respectively, neither of those totals is materially off what Sabathia has done in seasons prior in Pinstripes. The question then becomes why Sabathia is giving up more homers.

Here there appear to be two culprits: CC's fastball and his changeup. His fastball has been worth -6.7 runs this season, while his change has been worth -4.4 This is the second season that Sabathia has struggled with his fastball. It was worth -5.4 runs per game this year. That he can't get batters out with his changeup is a new development. He's normally combined that with his slider to have a devastating one-two punch combination.

Suddenly the picture becomes more clear. Sabathia has lost some velocity on his fastball. He may be struggling with one of his out pitches. If either of these pitches is located poorly, big league hitters are going to put it out of the park.

Sabathia will be a Yankee for many seasons more. His numbers are down this season, but he's still giving the Yankees value. The problem is that the Yankees need Sabathia to be one of the best pitchers in baseball and at least this year he's been below average. Hopefully for the Yankees Sabathia will be able to overcome this season and regain some of his lost form.