Matt Cain (SFN) altered his pitch selection significantly so far in 2011. During the previous three seasons, Matt relied on his fastball, working a change up occasionally. He used the heater 62.1% of time time, with the change tapped 11.6% of the time. The pitch barely shows up in comparison to the fastball:
The change is represent by the small tail down and toward a right-handed batter. In 2011, Cain throws fewer fastballs and more change ups, the change accounting for nearly a quarter of his pitches.
The tail stands out more as fastballs are down to 56.4% and changes are up to 24.2%. Why the change to the change? During the three previous seasons, Cain's fastball resulted in a .306 wOBA, while his change brought him a .282 wOBA. In 2011, those numbers are closer, but the change still wins .287 to .293 for the fastball.
Cain didn't stop with just throwing more change ups, he's throwing them farther down and out than before. In 2008-2010, he threw the pitch for strikes.
This season it's more likely to be out of the strike zone:
It's not clear that this shift really helped Matt, as he's getting more ball on the ground, but giving up more hits as well. That said, pitchers run the risk of becoming too predictable. Altering his pattern puts something new in the mind of his opposing hitters, and that works to the pitcher's advantage.