Intersting piece here from MLB insider Dan Szymborski. Basically he goes into great insight about how the Yankees don't hit off-speed stuff well. Here is a taste:
Against curves, Nick Swisher is hitting .154 and Brett Gardner is at .138. Even MVP candidate Curtis Granderson is hitting just .212 against the ol' No. 2. Derek Jeter is hitting .120 against changeups, Russell Martin .109.
Relative struggles against the curve and change are a new phenomenon for the Yanks. Last season, the Bombers were third in baseball against both pitches. A year before that, they were second in both.
For whatever reason, the Yankees have mostly fed on fastballs this season. The question this raises is whether it's a real effect or simply one determined by chance or the particular mix of pitchers the Yankees have faced.