The Hardest Fastball to Hit?

I am obsessed with evaluating pitchers and pitches. As part of a data request from Jeff Sullivan on the percentage of swinging strikes that pitchers generated off fastballs last year, I went looking through the PITCH f/x data and ultimately ended up generating a chart grouping each different pitch type from every pitcher in the big leagues in 2008, separated by whether or not the pitch was thrown to the same or opposite-handed hitter and whether the pitcher was starting or relieving.

That is, I have the results (in terms of result of the pitch) and can compare the results of, for example, fastballs thrown by Joba Chamberlain:

As a starter against a right-handed batter.
As a starter against a left-handed or switch-hitting batter.
As a reliever against a right-handed batter.
As a reliever against a left-handed or switch-hitting batter.

And so on, across each different pitch that he, or anyone, throws. This dataset is going to form the basis for more than a few posts going forward*, starting with this one. Among the first things that I did was strip out all instances of pitch totals under 100, feeling that 100 is a pretty decent sample of pitches given my strict categorization. Sorting that data by the percentage of pitches swung on and missed, I encountered right at the top, an amazing number. Ryan Madson’s changeup (as classified by MLBAM), thrown to same-handed hitters generated a swing and miss a whopping 36% of the time, about 5% higher than any other pitch by any other pitcher in 2008.

Scrolling down the list, I also noticed (not to my surprise) a lack of fastballs showing up. So I decided to see which pitcher first popped up. That name turned out to be Brandon Morrow. His fastballs as a reliever to right-handed batters clocked in at an impressive 20% swinging strike rate. What’s curious though was the spread in his results across the four categories. Here they are, presented in the same order listed above.

SP, Same hand – 10% (135 pitches)
SP, Opp hand – 7% (183 pitches)
RP, Same hand – 20% (219 pitches)
RP, Opp hand – 9% (216 pitches)

The 20% figure suck sticks out, doesn’t it? It’s worth pointing out that the average rate for fastballs from starting pitchers last year was just under 6%, so even at his worst, Morrow’s fastball appears to be an above average weapon for him. Still, it will be interesting to begin contrasting and adding 2009 data to this when the season begins.

*If there’s a question you want answered that you think this data can help with, shoot me an e-mail and I might be able to look into it for you.