The other observation to make with BABIP is in making predictions about how pitchers will do next year. Unless a pitcher has some unique ability to induce pop-ups and weak grounders (some do, like Rivera, most do not), in general an extreme BABIP regresses to the average, and pulls the pitcher’s ERA with it. So a pitcher who has a high BABIP and ERA in 2008 should see better luck on batted balls in 2009 and therefore a lower ERA. For my part, this is how I pick pitchers in fantasy baseball, to good result…

One should note the very high BABIP for pitchers like Andy Pettitte and Phil Hughes indicate a correction for next season, along with lower ERAs. By contrast, the very low values for Al Aceves, Edwar Ramirez, and LaTroy Hawkins beg for correction in the wrong direction next season.

Of course, when making conclusions about a pitchers’ BABIP, one should probably not break it down home-away, thus losing statistical power. But, I know that wasn’t your main objective here.