Swinging Less Is Better, At Least in the NL West
This year’s edition of baseball has produced some fascinating hitting performances. We’ve written a lot about Yasmani Grandal and his unprecedented batting line (a 134 wRC+ despite hitting .188). He’s done that in part by swinging at just 30.2% of pitches that he sees in ‘21, lowest in the majors by a wide margin. Max Muncy has also been incredibly selective, offering at just 35.4% pitches, the lowest rate of his career. These players have found that swinging less helps their game, but generally it’s not a trend that we’re seeing across the league. If anything, league-wide swing rates have increased (albeit marginally); this season’s 46.8 Swing% is the third highest since 2000. For every Muncy, there’s also a hitter who likes to swing at just about everything. Salvador Perez and Tim Anderson, for example, have swing rates of 60.3% and 59.3%, respectively.
The outliers are certainly interesting, but just how little can a big leaguer swing and still get away with it? What we’re talking about here are O-Swing% and Z-Swing%. By themselves, these are telling statistics, as hitters with a high O-Swing% strike out a lot more than those with a low O-Swing%.
For context, a 5% increase in O-Swing rate on average results in an increase of 1% to strikeout rate. This relationship is even stronger when it comes to drawing walks.
So far in ‘21, a 5% decrease in O-Swing rate on average results in an increase of 2% in walk rate.