Kevin Kiermaier missed a good chunk of the season after breaking his glove hand in late May, and that’s a shame, because when Kiermaier is in the field, he’s among the most exciting players in baseball. Kiermaier is must-see television with a glove in his hand. Decidedly less so at the plate. He’s been roughly a league-average hitter through 1,100 career plate appearances, and so it’s understandable that when we’re paying attention to Kiermaier, it’s usually for his defense.

But I want to flip the script for a minute. The Rays are bad, and Kiermaier missed time, and we’re usually paying attention to the defense, so this may have been easy to miss, but Kiermaier’s undergone some rather radical changes at the plate, relative to last season. Cutting to the chase:

Kevin Kiermaier’s newfound patience

• +7.4% increase in walk rate, second-highest among 249 batters with 200+ PA in 2015 and 2016
• -8.2% decrease in swing rate, second-largest drop among same pool of 249

Last year, Kiermaier walked in just 4.5% of his plate appearances, and this year, it’s nearly tripled its way up to 11.9%. Another way of looking at that: he went from walking about as much as Alexei Ramirez to walking about as much as Edwin Encarnacion. Kiermaier’s got great speed, and the more often he’s on base, the better. He’s presently running a career-high on-base percentage, despite an uncharacteristically low BABIP.

Where things really get interesting, to me, is the splits. Now, Kiermaier’s sample for the season is already small, and so of course breaking that into even smaller samples can be dangerous — he’s only got 54 plate appearances against lefties — but bear with me:

• vs. LHP: 16.7 BB%, 18.5 K%, 110 wRC+
• vs. RHP: 10.6 BB%, 17.7 K%, 94 wRC+

Kiermaier’s walked against lefties nearly as often as he’s struck out, and as a result he’s been better-than-average against his same-handed foes. The reason I’m drawing particular attention to this is because perhaps the biggest thing holding Kiermaier back from becoming a bonafide superstar in his first two years in the league, rather than an under-the-radar superstar, has been his trouble hitting lefties. Through his first two years and 229 plate appearances, Kiermaier ran a 61 wRC+ against lefties, walking just 3.5% of the time while striking out at a 24% clip. Now revisit those numbers from above.

The cause here is twofold. His 11% decrease in swing rate against lefties is the most extreme drop of any left-handed batter from last year to the next. So, it certainly looks like he’s simply taking a far more patient approach at the plate, since trying to hit lefties the last couple years hasn’t worked out. It’s working, so the plan looks good. But then also, Kiermaier’s seen baseball’s biggest drop in zone rate (-5.7% from last year), so maybe the lack of swinging is simply a product of not getting pitches to hit?

That part is hard to explain. Kiermaier was never an overaggressive hacker, and he’s never been a big threat at the plate, so it’s hard to see why he’s not seeing more strikes. FanGraphs database guru Jonah Pemstein ran the numbers, and the lefties Kiermaier faced last year ran a cumulative walk rate of 8.0%, and the lefties he’s faced this year have a cumulative walk rate of 8.1%, so it’s not like he’s faced an unusually wild sample of pitchers. No matter the case, Kiermaier deserves the credit for laying off the balls and taking the walks.

For now, this remains an open case, but it’s something to monitor. Kiermaier’s spike in walk rate is certainly noteworthy, though it’s difficult to tell whether that’s more a product of a truly newfound approach, or a sudden and puzzling drop in number of strikes seen. Solving lefties was about the only missing part of Kiermaier’s game. If this change is real, perhaps it could be the ticket out.