Which Yankees best embodied the air ball revolution in 2017?

This offseason has been historically quiet. The only deals being made seemingly are two-year contracts for setup men, while big free agent signings and trades remain merely a dream. Whispers of collusion are growing louder. The primary storyline surrounding MLB right now is that of a frozen hot stove.

Before this frigid winter, though, there were some different storylines that dominated baseball discussion. The two biggest among them were the story of the juiced ball, and the “air ball revolution”. Before the league slammed on the breaks in the offseason, all anyone could talk about was the explosion of power and offense league-wide, and why such an explosion even occurred.

With the hot stove dormant, there’s no better time to return to those stories. Josh took a look at the impact of the juiced ball on the Yankees earlier in the week, so now, let’s examine the air ball revolution. More specifically: which Yankees best embodied the fly ball trend in 2017?

There’s no one-size-fits-all way to identify a member of the air ball revolution. There are no group meetings for proponents of the revolution. They aren’t handing out pamphlets.

So, my entirely arbitrary criteria to determine which Yankees best embody the trend towards fly balls depends on a few things: whether the player demonstrated a clear shift towards putting the ball in the air last year, and whether or not such a shift actually seemed to help.

I think that last bit is important. If a player alters his batted ball profile to try to improve his production and fails, he doesn’t really embody the spirit of the revolution. With that in mind, two Yankees are clearly among the finest air ball revolutionaries in all the land: Brett Gardner and Didi Gregorius.

Both took steps forward at the plate in 2017. In Gregorius’ case, he managed a career-best offensive season. Both looked radically different than they did previously, and both did so by fundamentally altering the shape of their profiles as hitters.

Gregorius has a case as one of the largest beneficiaries of the shift towards fly balls (and of the juiced ball, for that matter) in all of baseball. Per Baseball Savant, Gregorius’ average launch angle on batted balls increased by over four degrees, from 13.5 degrees to 17.6 degrees, from 2016 to 2017. That was the fifth-largest such increase in the league among players with at least 400 at-bats across each of the past two seasons.

After running groundball rates of 44% and 40% in 2015 and 2016, respectively, Gregorius posted a career-low rate of 36%, per FanGraphs. His fly ball rate jumped to a career-high 44%, and his line drive rate remained at a respectable 20%. He didn’t actually hit the ball any harder (his exit velocities have been below average each of the past few years), but rather, Gregorius was simply hitting more fly balls and fewer harmless grounders.

It’s hard to argue that the change helped propel Gregorius. His 107 wRC+ was easily a career-best. He became the first Yankee shortstop to ever smash 25 home runs. He set career-highs in slugging and isolated slugging. It’s difficult to say how much credit to apportion to what looks like a new approach, and how much to the livelier ball. Regardless, the combination led to the Yankees employing an All-Star caliber shortstop with both a glove and pop.

Gardner, too, seemed to flourish in part due to the shift towards fly balls. His average launch angle increased by 2.9 degrees, the tenth-largest such increase. It only jumped up to 9.2 degrees, not quite at the league average, but it still represented a significant change for Gardner himself.

His fly ball rate of 33% was also fairly middling, but was sky-high compared to his 2016 rate of 27%. After running one of the highest groundball rates in baseball in 2016 at 52%, he slashed that all the way 44%.

Those rates are pretty close to league average, so you could argue that Gardner isn’t one of the strongest members of the fly ball cavalcade. Yet even if Gardner’s rates of air balls aren’t far above average, his shift from a groundball-happy slap hitter in 2016 to a hitter with a profile in the middle ground is among the largest changes in the league. That jump from far below up to average is just as large as the jump from average to well above.

Gardner’s production didn’t quite skyrocket like Gregorius’, but his 108 wRC+ was still strong, and his best in three seasons. He set career-highs in slugging and home runs. He too likely benefited disproportionately from the juiced ball, yet his success at the plate is still probably explained by both the lively ball and his shift towards air balls.

The obvious upshot is that there’s no guarantee that either will keep this up in 2018. They looked very different as players in 2017, and players that show up different often regress to the mean. Still, when players appear to show a shift in strategy, and that shift helps them, they have every reason to try to maintain that change. Keeping their batted ball profiles (and hoping for a still-lively ball) in 2018 may just be both Gardner’s and Gregorius’ best bet at continuing to hit a career-best clips.