Recently, the excellent stats-oriented baseball site Fangraphs added a feature to its player pages: pitch type values. With this cool new stat, we can see exactly who on the team has the best fastball, curveball, slider, etc.
Using data from Baseball Info Solutions, they break out every pitcher's pitches by type (fastball, slider, etc.), sum the outcomes of each pitch thrown, and count the total runs allowed above and below average by pitch type. A fastball of perfectly average effectiveness rates a 0.00 pitch value. An above average fastball would result in fewer runs allowed, however, and pitch type values tell us exactly how many runs that pitch is worth. The stat is calculated both as a counting stat--total runs allowed for the season--and as a rate stat--average runs allowed per 100 pitches thrown.
I will caution that there's some real potential for small sample size errors here. And the BIS data on pitch types isn't perfect--change-ups and fastballs get mixed up, as do sliders and curves. Still, it's pretty good data,
So enough of the sausage-making. Who's got the best stuff on the staff?
Among current Nationals, the best fastball belongs to that fireballer Ron Villone, at 3.34 runs above average per 100 pitches (R/100). Just goes to show what location can do. Scott Olsen has the worst fastball at -3.24 R/100. Among starters, only Shairon Martis has an above-average fastball at +0.11 R/100.
Looking at breaking pitches, Ross Detwiler's Uncle Charlie is the best pitch in the rotation at 4.50 R/100. Jordan Zimmerman's slider is the second best at 1.57 R/100. Martis's curve is a terrible -6.35 R/100, and Zimmermann's isn't very good either, at -1.33.
Zimmermann also has the best change-up, at 3.11 R/100, followed by Lannan's at 1.53. Detwiler's change-up is a disastrous -8.69 R/100--that's the pitch that he needs to work on at AAA.
Again, take all this with a large dose of small sample size salt, but I'll be interested to see how these numbers evolve over the season.