This article is part of our MLB Barometer series.
The assumption was that a high BABIP for a pitcher was the result of bad luck, while a low BABIP was the result of good luck. For hitters, a high BABIP was good luck, while a low mark was bad luck.
Those of us who bought into it as a tool to find improperly valued players were largely wrong, as we were completely overlooking the fact that a pitcher with a great defense behind him would have a much better chance of posting a low BABIP, since balls in play against that pitcher could be more frequently turned into outs. It overlooked the extremes at the opposite end of the defensive spectrum as well, among other things.
Even with a flawed understanding of what BABIP could and could not tell us, we may have been accidentally right – telling our readers and listeners to steer clear of Carlos Zambrano due to his good fortune the year before, only to have his BABIP nearly repeat, while his home-run rate or walk rate soared and his ERA went through the roof.
In addition to overlooking the role of defense, we were discounting the quality of contact allowed by a pitcher. Pitchers who induced a lot of weak contact, or specifically, infield flyballs, would have been capable of sustaining a lower BABIP than their peers who didn't record as many outs that way.
With the massive increase in qualitative data that