What can kick start the stalled development of Max Kepler?
In the offseason after the 2019 season the baseball decision makers of the Minnesota Twins organization looked like they had made a shrewd bargain to lock up one of their young core pieces to a multi-year extension.
At that point, Right Fielder Max Kepler had agreed to a modest $35-million contract that covered the 2019 through 2023 seasons. Kepler made good on that deal by having the best season of his career in its first year.
In 2019, Kepler hit .252 and slugged .519 while slugging 36 homers, 32 doubles, and scoring 98 runs. The summarized result was the first above average offensive season of his big league career. By Weighted Runs Created Plus (wRC+), a comprehensive rate statistic that quantifies a player’s total offensive value, Kepler was 21 percent better than league average (121 wRC+, league average is 100) in 2019.
Given his top 100 prospect pedigree and age at the time of signing (25), Kepler seemed poised to continue to develop to even higher levels of production. It appeared the Twins organization was positioned to profit handsomely for the foreseeable future.
But that’s not what has happened.
Less than two short years later, through the pandemic shortened 2020 season and the first month and change of the current 2021 season, he has not resembled anything close to the player he appeared to be in 2019.
Kepler has hit .219 and slugged about .400 since his breakout campaign. His combined wRC+ across 2020 and 2021 is 94 -- almost exactly in line with the 95 wRC+ he compiled from 2015 to 2018. If you factor in that his primary right field position has offensive expectations that are marginally higher than the overall league average his numbers from any season besides 2019 get painted in a more negative light. His Isolated Power (ISO), a stat generally used as a measure of extra base hit ability, has declined from .267 in 2019 to an even .200 since.
Instead of establishing new performance baseline out of his big season, Kepler mostly just returned to prior form. That prior form -- somewhat below average offense combined with well above average defense -- is still valuable and places Kepler as one of the top 10 or so right fielders in all of MLB.
But it’s not what we expected to happen.
What is behind this? And more importantly, what changes might restore Kepler to his 2019 level?
Before jumping in to breaking down his numbers, it’s important to put his most recent production in context.
The full 2020 season was only 60 games, barely more than a third of a typical full season. It was full of abnormal characteristics and disruptions due to the ongoing pandemic. Add in a little over a month’s worth of play this season, with many of those same pandemic compensatory measures in place, and it all adds up to a very strange half season. Baseball history is littered with examples of players struggling for half a season or more before righting the ship, and that’s without the additional burden of the pandemic impacts. It could be the case that this depressed performance is just a short term, small sample size blip.
On top of that, Kepler missed time last season with an injured list stint for an adductor strain and some more time this season with a COVID-19 infection. It’s reasonable to think that the combination of the strange and unpredictable environment and injuries have prevented him from finding the good rhythm he had in 2019.
With all of that in mind, let’s dig in on the Statcast data and see what was different about that special season and what might be keys for helping him restart his positive development curve.
Comparing Kepler’s recent statistical profile to 2019 offers a few mixed signals.
On the positive side, he’s reduced how often he’s chased pitches out of the strike zone from a slightly-better than league average 28% in 2019 to a very good 24% last season to an outstanding 21% (84th percentile) so far in 2021.
Also on the positive side is that Kepler has increased his line drive percentage from 22% in 2019 to 30% last season and 28% this season. Line drives are the class of batted balls that are most likely to go for hits.
Swinging at fewer pitches out of the strike zone and hitting more line drives should be good things. Why hasn’t stronger production followed?
The issue is that those line drives have come at the expense of fly balls, which are the class of batted balls that are the most productive in terms of run creation. Fly balls tend to result in extra base hits, especially home runs.
Kepler’s 2019 power breakout was fueled by a career-best 30% fly ball percentage. Last season that was down to 21% and it has dropped to 17% so far in 2021.
Among fly balls, the most productive are those that are pulled by the batter. And here is another issue. The left-handed swinging Kepler has not been pulling the ball like he did two seasons ago.
Pulled fly balls are what yielded so many of those home runs in 2019, and the vast majority of his career homers, as this spray chart shows:
Kepler pulled 50% of his batted balls in that breakout season. But his pull rate was down to about 43% last year and is down again to 36% this year. Beyond just the home runs, Kepler is more productive overall when he pulls the ball:
With numbers making it so clear that pulling pitches is in Kepler’s best interest, why isn’t he doing it more?
Part of the explanation might be a more passive overall approach. Pulling the ball in the air with authority requires being decisive and getting the bat out in front of the plate on swings.
In 2019, Kepler was aggressive in this way. He had the highest rates of swings (49%) and swings at first pitches (41%) of plate appearances of his career. Since, he’s swung less often overall (about 45%) and taken more first pitches (1st pitch swing percentage down around 32%).
Pitchers have noticed the more passive approach and responded by attacking Kepler more aggressively inside the strike zone. The percentage of pitches thrown to him inside the strike zone has increased noticeably -- from 47% in 2019 to 51% so far in 2021.
The combination of all of the above has improved his plate discipline, as shown in the chase numbers above, but appears to be limiting his ability to drive pitches in the air. Perhaps an adjustment, to return to a higher level of aggressiveness, will be a key that helps Kepler return to his 2019 star form.
In addition to the fly balls and pulling pitches, a third factor affecting Kepler’s performance is his production against left-handed pitching. Early in his career Kepler struggled majorly against southpaws. He started to produce at a passable level against them in 2018 and then figured out the puzzle in 2019. His 129 wRC+ against left-handers that season actually outpaced his 118 wRC+ production against right-handed pitchers. It didn’t seem to be a fluke -- his new production level against left handers was supported by the advanced metrics.
But, in 53 plate appearances against lefties last season, Kepler hit .128 and slugged .170 for a total production of just 5 wRC+. That’s not a typo, five. So far, in a very small sample in 2021 (27 plate appearance), his numbers versus lefties are not much better -- .167 batting average, .333 slugging percentage.
However, there is reason for optimism. Statcast measures how hard batters hit pitches with a statistic called exit velocity. The harder a batter hits the ball the better is the general guideline. By that measure, Kepler is hitting as well as he ever has against left-handers, averaging almost 93 miles per hour exit velocity, the best mark of his career. In addition, Kepler has cut his swing and miss rate against left-handers in half (13%) from last year’s 26%.
Hitting the ball harder and more often are both very positive signs that Kepler is rounding back into form against left handed pitching. That will go a long way toward bringing him closer to the player he was in 2019. Now, if he’ll make an adjustment to be a little more aggressive and swing more often against all pitchers, like he did in 2019, maybe he can get all the way back to that level.