Mike Moustakas Swings for the Fences

Currently 5.5 games out of first place in the AL Central, it’s still unclear whether the Royals will go for it one last time with a number of the same pieces from their championship season, or if they’ll perform a massive sell-off of multiple potential free agents. Lorenzo Cain, Eric Hosmer, Jason Vargas are among those who could be moved. Perhaps Kelvin Herrera, just another season from free agency, could be gone as well. Mike Moustakas might not get the notoriety of some of his teammates, but whether the Royals go all-in or sell, it’s Moustakas who should play the most important role.

Just a few seasons ago, Moustakas was a part of a disappointing group of formerly heralded prospects on the Royals’ major-league club. In 2014, as the Royals shocked just about everyone with their run to the World Series, Moustakas finished the season with a line of .212/.271/.361, good for just a 75 wRC+. Even with solid defense, the result was a barely replacement-level season. Moustakas had a problem: he was a fly-ball hitter in a spacious park. In the 2014 postseason, Moustakas hit four homers in his first six games, but was mostly quiet the rest of the way.

That power from the 2014 postseason didn’t really carry over to 2015, but once the summer hit — around the same time baseballs began flying out of the park at a much greater rate — Moustakas surged. Due to a knee injury, he recorded only 113 plate appearances the next season, but the power showed up in limited time — and it has continued in a big way this season. The graph below shows Moustakas’ 15-game rolling ISO, allowing us to see where Moustakas took off.

In the first half of 2015, Moustakas had become a ground-ball hitter, and the 35% fly-ball rate he recorded over that period would have been the lowest of his career if it had continued. He was pairing those grounders with a very low 11% strikeout rate, .315 BABIP, and very little power. The result was a 115 wRC+ over the first half, not too bad for a guy with a career 82 wRC+ in nearly 2,000 plate appearances. As for the change in approach, maybe it was because he was slotted at the No. 2 spot in the lineup and felt he had a role to play. He hadn’t ever been a guy to run up a decent BABIP on account of all the fly balls, so it’s unclear whether this strategy of grounders was going to work long term. We’ve never had to find out.

Moustakas went back to his fly-ball ways in the second half. Maybe it was the trade for Ben Zobrist and subsequent drop in the batting order that caused him to return to his old approach. Unlike in previous seasons, though, his fly balls started leaving the park. He was pulling the ball more, too. In the first half, his home-run rate on fly balls (HR/FB%) was 7.5%, pretty close to his career rate, but in the second half it was 14.5%. Increase the number of fly balls and the frequency with which those flies leave the yard, and you end up with 15 second-half home runs.

That second half mini-breakout looked like it might lead the way to a big breakout in 2016, which saw Moustakas hit seven home runs and record a .260 ISO over the first month and a half. He missed the remainder of the season with knee surgery, though. Healthy once again this year, Moustakas is taking an even more extreme fly-ball approach, even after returning to the two-spot in the lineup. He’s both swinging and striking out more than ever before. He’s walking less, too. And while he hasn’t entered Ryan Schimpf Territory (65% FB rate) or anything, Moustakas’s 44% fly-ball rate sits among the top 25 in baseball; his 50% pull rate is in the top 20. The only players with higher numbers in both categories are Joey Gallo, and Mike Napoli, and teammate Salvador Perez, a group that doesn’t lend itself to a high BABIP. Gallo and Napoli strike out twice as much as Moustakos, while Perez walks two-thirds as often, giving Moustakas significant advantages over all three.

Moustakas is simply swinging and missing a lot more, and it’s working. Outside of the zone, Moustakas used to swing about one-third of the time. He’s up to 41% this year and his contact rate has gone down from around 75% to 66%, which is actually a good thing. Moustakas’ high contact rate hampered his ability to make good contact in the past and got him optioned to the minors a few years back. He’s swinging at more pitches in the zone, too, with his 75% swing rate ranking third in all of baseball. He’s maintained a relatively high rate of contact there, at 89%.

So we have a guy with a fly-ball swing, willing to miss a little bit more when the pitch goes out of the zone, but maintaining the contact rate in the zone. Moustakas is not a part of any fly-ball revolution. He’s always been a fly-ball hitter who didn’t strike out very much. That isn’t a common combo, with Ian Kinsler, Josh Reddick, and Moustakas himself representing the only batters since 2014 with at least a 41% fly-ball rate and under a 15% strikeout rate. So what does a high-zone-contact, high-fly-ball-rate swing look like?

Here’s one example:

Pitchers don’t pitch Moustakas in the zone, his 44% rate currently sitting in the bottom 10% of batters this season. He’s swung and missed a lot on the slider and change, per Brooks Baseball. Those pitches tend to move out of the strike zone, so it’s possible he could see a lot more of them in the near future and need to make adjustments. Right now, though, he’s found a pretty good balance based on the way he’s been pitched.

Since the trade deadline of 2015, Moustakas has recorded 549 plate appearances, 34 homers, a .270/.328/.539 batting line, a 130 wRC+, and 4.0 WAR. The only third baseman in baseball with a higher ISO than .268 last season was Nolan Arenado’s .274 and he plays in Colorado. Adrian Beltre, Kris Bryant, Matt Carpenter, and Josh Donaldson were the only third basemen to exceed 130 wRC+. Include his decent defense, and Moustakas is comfortably one of the top-10 third basemen in baseball. That could be worth a lot to the Royals, either in Kansas City or somewhere else, as the summer progresses.