I was fiddling around with the new gameday data … here’s what I came up with.
That is Peavy’s last start against the Mets. He struck out 11 in 6 innings that night, but also walked a season high 5 batters. The y-axis is velocity and the x-axis is the pitch number for that start. For example, the lonely data point in the botom left hand corner is an 83 mile per hour pitch … Peavy’s 14th of the game. The only real trend I can pick up is that he went to more off speed stuff as the game went on. In pitches 80-100, he only threw 5 balls over 90 mph.
Here’s his start before that against the Astros. Peavy was even more dominate this outing, striking out 11 and only walking just 2 in 7 innings of work. Again, it seems to me he goes away from the fastball a little bit late. Now, of course, this could just be pitching to situation or something (ie, as the game situation gets more crucial, he goes to the slider more often …). It may not be that he actually changes his pattern late, but it sure seems that way.
Finally, here are all of his pitches from his last two starts, ordered by velocity.
You can see that a lot of his pitches register at 92 mph+. In fact, 111 of his 212 tracked pitches were 92+.
From what I’ve read about the PITCHf/x system, the pitch speeds should be very accurate. I used the “start speed” which is the velocity of the pitch 50 feet from the plate. Of course, there could be some slight errors in what’s being recorded. I don’t think it’s perfect by any means (but it’s pretty damn accurate).
Anyhow, this is just the very tip of the iceberg with this kind of analysis. There is a lot of great work being done. If you’re interested in reading some great articles and learning more about PITCHf/x …
Anthony at Friar Watch has done a lot of stuff with it.
Alan Nathan has some great info on his Physics of Baseball website.
Mike Fast is tracking it at Fast Balls.
I’m hoping to get to a point where I’ll be able to do some stuff like that. Uh … that might take a while. It’s fun to look into, though.