The above shows which starting pitchers are not getting the strike calls they should according to PitchFX data. Ervin Santana seems to have been royally squeezed in his two starts this year. Here's a heat map of all his pitches that were called balls so far in 2012:
Now take a look at last season's list:
Justin Masterson is the one name that has reappeared in the 2012 top ten list of squeezed starting pitchers. His name shouldn't be a surprise - he's one of many sinker ball pitchers that made the top ten for the 2011 list. The high and low parts of the strike zone are often the most difficult for umpires to call consistently correct since they change slightly batter by batter.
Expect to see more sinkerballers sneak their way into the 2012 list as the season progresses.