Fascinating post by Josh Kalk at The Hardball Times today talking about the aging curve of fastballs (and, wow, does this intro look like pingback spam or what?).

Even though he has plenty of necessary disclaimers on the data, for those of us who watch baseball, the trend shouldn’t be surprising.  What Josh has done is quantify that which we all kinda figured: pitchers throw harder sooner and slower later.  The peak at 29 and subsequent steep drop-off aren’t really surprising, either.  I mean, it just seemed like this happened.

It’ll be hard to fully quantify the aging curve drop-off, though.  As pitchers get older, they rack up tons of pitches on their arms.  As they get older, they become pitchers instead of just throwers.  One can put in a lesser effort versus the Patron Saint of Outs Neifi Perez than they can Lance Berkman.  What role does the weather play?  Situational pitching?  Number of pitches?

But what does it all mean?  Harder throwers tend to get more strikeouts.  Can this be used, for example, when you are up by two runs in the eighth, but the other team now has guys on 2nd and 3rd with no outs?  Wouldn’t this be an opportune time for a strikeout?  Can we use pitch counts along with the curve to better predict performance?  You gotta think Nate Silver, inventor of PECOTA, drooled on his keyboard when he saw this.

Being a geek, it’s fun to get geeky with information like this.  And it’s also fun to think about how much Joe Morgan’s head exploded when he saw this.