Max Kepler is pulling the ball with aggression

Max Kepler has been a solid player for a couple of years now. He’s always drawn walks and avoided strikeouts better than the average hitter. He’s a good defender in the outfield. He just hasn’t had a ton of power for a fly ball hitter. He put up 2.6 fWAR last season, but his wRC+ was just 97, or just a smidge below average.

This year, he’s already blown by last year’s WAR total at 3.9. He’s hit 34 home runs, brought his slash line up to .254/.334/.532, and his wRC+ is 122.

He’s more or less the same hitter. His strikeout and walk rates haven’t moved. Kepler hasn’t increased his hard-hit rate by much, at least not enough to explain this jump in his numbers. Kepler’s average and max exit velocity is the same. He’s hitting the same number of line drives, ground balls, and flies.

There isn’t a player in the majors that has improved his pull percentage more than Max Kepler. Per FanGraphs, Kepler’s pull rate has risen from 43.1 percent to 55.3 percent. As a fly ball hitter, that’s translated to an increase in power. Kepler, who just broke the record for home runs by a European born player, is at career bests in homers, ISO, and slugging.

Kepler is pulling a larger percentage of his fly balls, and it’s remarkable that he’s done this while maintaining his contact ability. It’s easy to see how that improved the results. Pulling nearly half of his fly balls has pumped his ISO on fly balls nearly .200 points.

That’s consistent with the league-wide trend. Slugging on pulled fly balls in 2019 is 1.936. Straightaway it’s just .763, and to the opposite field it’s just .570. Getting the ball in the air to the pull side is obviously the best outcome.

Kepler is pulling more and more balls in the air, so that makes his breakout look for real. It’s always important to be wary of changes in pulled fly ball rates. Nick Gerli at Pitcher List found that the year-to-year correlation for pulling balls in the air isn’t strong. This makes sense. Even for a heavy fly ball hitter, they might not get a large sample of fly balls over a season.

Kepler might not carry this part of his game over to 2020. We’ve already seen Kepler’s pull rate on flies drop this season. In the second half, Kepler’s pull rate on fly balls is 38.3 which is closer to his career average. If a year of fly balls is a small sample, then a month and a half is teeny tiny. We could see this rebound to his first half numbers by the end of the season. We could just as easily see them fall again.

He has made slight adjustments to his approach, however. He’s been far more aggressive at the plate. His z-swing has risen by 10 percentage points from 65.3 to 75.5 percent, and he’s concentrating more of those swings on pitches over the heart of the plate.

Here’s Kepler’s zone profile from 2018. Note how low is swing rate on pitches middle-middle.

FanGraphs

Here’s his zone profile again but in 2019. Only rarely is he allowing pitches down the pipe to go by.

FanGraphs

Per Baseball Savant, Kepler’s swing percentage on meatballs rose from 68.9 percent to 85 percent. He went from very politely letting pitchers make mistakes to crushing them without mercy. He’s also been far more aggressive on the first pitch when he’s most likely to get a fastball. His first pitch swing percentage is 40.9 and MLB average is just 28.2 percent.

This aggression might have been the cause of his increased fly ball pull rate. If that’s the case, we might expect a similar season from Kepler next year and down the stretch as his Twins fight for the NL Central.

Kenny Kelly is a writer for Beyond the Box Score and McCovey Chronicles. You can follow him on Twitter @KennyKellyWords.