We've seen it happen time and again, and the numbers agree: When a player shows power, pitchers adjust. They try to defuse that power by throwing fewer pitches in the zone and fewer fastballs.
What we'd like to do here is turn the tables on this process by analyzing various hitters' power situations based on which batters this season are seeing fewer pitches in the zone and fewer fastballs, and vice-versa.
To do so, we'll use a few cool stats. The newest is Heart%, a stat created by Bill Petti that measures how often a pitch crosses the plate in the heart of the strike zone. We'll also look at O-Swing%, which measures how often a hitter reaches at pitches outside the zone. And we'll judge power by using Isolated Slugging Percentage -- slugging percentage minus batting average, or basically an extra-base hit rate.
Examining these statistics can help us identify which hitters likely have sustainable power breakouts and are worth targeting or keeping -- and which fading sluggers would be best to avoid or let go.