Wednesday: Batting Average on Balls in Play (BABIP)

Batting Average on Balls in Play (BABIP) measures the opponent's batting average on all batted balls that the defense manages (in other words, foul balls that are caught for outs and everything fair except for homeruns, ground rule doubles, etc). It is often used as a measure of the strength of the defense behind the pitcher, and how high or low it is can be used to predict how a pitcher might perform in the future. The league average is generally floats within a few points of .300.

It can also be used as a measure of a team's defense over the course of the season: the Rangers as a team posted a .322 BABIP in 2008, worst in the majors. In contrast, the defense-conscious Tampa Bay Rays grinded out a .285 BABIP, best in the majors. Think of how many runs that saves (or adds).

While sifting through the Rangers team BABIP statistics today, everyone's looked about as expected except for those of Kevin Millwood and Eddie Guardado:

Eddie Guardado: 2008 BABIP (with Rangers): .240 Career BABIP: .290

I have to admit that I was surprised with "Everyday" Eddie's strong season in 2008. It was great; he's the scrappy underdog that we all root for inside. But perhaps he got a few too many lucky bounces this last season, as showcased by his .240 BABIP with the Rangers in 2008. His luck started to catch up with him when he arrived in Minnesota, however, which his .427 BABIP from that point on suggests. Look for Eddie's 2009 BABIP to regress towards his career BABIP of .290, and hence for his ERA to inflate as well.


Kevin Millwood: 2008 BABIP: .366 Career BABIP: .308

Are you kidding? .366? The only pitcher on the 2008 Rangers that was worse was Luis Mendoza (with a sparkling .385). So, when the ball was put in play against Millwood last season it was like Ichiro was at the plate. Believe it or not, this isn't much worse than his .348 BABIP in 2007. And it's not as if this is a career trend: his career BABIP is fairly average at .308. Unsurprisingly, the only two seasons that Millwood has posted an ERA of higher than 5.00 have been the last two seasons. Millwood has suffered from bad luck and bad defense long enough -- it is time for a change. Look for Millwood's lofty .366 BABIP to regress towards his career average of .308. Along with our (supposedly) shored up defense, this should go along way towards an improved Kevin Millwood in 2009.