Batting Average on Balls in Play
Batting average on balls in play: home runs and strikeouts taken out.
What it actually is. Batting average on balls in play: how often batted balls that stayed in the park turned into hits, with home runs and strikeouts removed from both sides.
What a scout reads off it. This is the single best luck detector in baseball. A hitter fifty points above his own career figure is having a lucky year, not a career one, and a pitcher fifty points above his is about to look much better without changing anything.
Where the lines are. Around .300 is the leaguewide gravity this number is pulled back toward. Hitters with real speed or elite contact quality hold higher figures legitimately, which is the exception worth checking before crying luck.
How it lies to you. It is a detector, not a verdict. Look at exit velocity and line drive rate before deciding a change is luck, because a hitter who started hitting the ball harder will hold a higher figure.
Batter's Eye: look up anything in baseball