BABIP is a measure of batting average when the ball is put in play on the baseball field. Before talking about the details, let’s look at one quote and two reasons BABIP is useful.
“The pitcher has limited control over what happens once the ball is put in play. This was discovered 20 years by Voros McCracken. The hitter has more control than the pitcher.” —Jack Sommers
Because pitchers don’t have control (except when they participate in fielding the ball in play), BABIP can be a tool that indicates when a pitcher’s hits allowed were more or less than expected over the long term.