Monday, June 29, 2009
Yesterday, Tommy Hanson took it to the Red Sox despite fighting off the flu, and pitching in temperatures that reached well beyond anyone's comfort zone. He's now got a record of 4-0, with an ERA of 2.48. He hasn't allowed a run in his last 3 starts, and looks to be dominating every team he faces.
It would seem that Hanson -- at the ripe old age of 22 -- is well on his way to establishing himself as one of the Brave's premier starters, and perhaps one of the best in the league. But let me throw out a few numbers at you and let's see what really lies below the surface.
Hanson's current K/BB ratio is 1.06, his groundball rate of 31%, he has a WHIP of 1.41, and a home run rate of 5%. His FIP (Fielding Independent Pitching, which measures the number of runs a pitcher is likely to allow in 9 innings given his other stats) is 5.10. National League pitchers with similar stats include Ian Snell, who was recently demoted to AAA after posting an ERA of 5.36, Micah Owings, Jeff Karstens, John Maine, and Shairon Martis. Not exactly a who's who list of ace pitchers.
So, if Hanson's peripheral stats put him in such poor company, why the 4-0 record and stellar ERA? The missing link here is probably the fact that opposing hitters have posted a BABIP of just .239 against Hanson this year at the major league level. That means, that for every ball put into play against Hanson, only 23% of them are finding a gap in the defense.
It's possible that hitters are having a difficult time making solid contact with Hanson's pitches, and the .239 BABIP will prove to be the deciding factor in his future dominance. But if we consider that Hanson has posted a BABIP generally between .260 and .290 in the minors, it is only appropriate to assume that pitching in the majors will result in a BABIP of at least .260 or more. As an example, take Tim Lincecum, perhaps the most dominant young pitcher in the nation. Throughout the minors, Lincecum held batters to a BABIP between .220 and .250, 40 points below Hanson's minor league record. Since reaching the majors, Lincecum has allowed a BABIP between .296 and .336, essentially 60 to 90 points above Hanson's current pace.
If we measure Hanson's BABIP success against other Brave's pitchers, the picture doesn't get much better. Jair Jurrjens has a BABIP of .298 for the year, Javier Vazquez currently sits at .305, and Derek Lowe has a BABIP of .309 despite posting a ground ball rate of 54%.
The most likely explanation for Hanson's current success is probably a bit of luck, limited exposure to opposing hitters, and a small sample size. Given enough time (say 6 to 8 more weeks), there's about a 80-90% chance that Hanson's BABIP reverts back to somewhere around .300, and his ERA drifts upwards of 4.00. It's not absolutely set in stone, but the evidence suggests that Hanson isn't as good as he looks, and sooner or later the results will prove to be less than stellar. As a Brave's fan, I hope he keeps it up, but as a realistic stats fan, I don't see it happening. If I were Frank Wren, I'd sell high and trade Hanson for a big time bat (Adrian Gonzalez would look great in a Brave's uni).