Playing around with some PFX tonight. I wanted to plot a graph of fastball height location vs. frequency thrown. I selected Matt Cain and Jeremey Affeldt as comparisons.
Big thanks to Joe Lefkowitz’s Pitch F/X Tool for providing the data. My deskstop is still packaged away, and with it my database. All numbers from the 2009 season.
The two horizontal gray lines indicate the standard strike zone by height. Matt Cain, being a flyball pitcher that goes for strikeouts, is more likely to pitch batters up in the zone with his fastball. Cain has a FB% (flyball percentage) of 45% over his career — indicating that he’s more likely to give up flyballs than any other batted ball. His career K/9 of 7.5 is above average for a starting pitcher in the National League. In 2009, the average SP in the NL struck out 6.8 batters per 9. Cain is almost a full strike out better than league average. This fastball location profile seems to mesh with what we would expect for Cain’s pitcher-type. Cain works up in the strike zone with his heat.
Affeldt had an interesting season in ’09. He owns a career GB% of 48.8% which indicates that he’s got some groundball tendencies. But, last year Affeldt’s ground ball percentage shot all the way up to 65%. As a result, Affeldt induced 18 double plays — leading all relievers in baseball. As you can see from his frequency graph, he kept his fastball down in the zone (much lower than Cain) where batters are more likely to hit it on the ground. I don’t think Affeldt is a true talent 60%+ groundball pitcher, but his game plan should remain the same: keep the ball down. Over his career since he switched to relief full-time, he’s been successful by following that approach.
It all adds up to another reason why I like baseball so much. You’ve got two pitchers with two great fastballs, but they use them in two opposite ways to achieve success.