What the return of two superstars can tell us about Didi Gregorius

Didi Gregorius began extended spring training games Monday, the most positive news yet on his recovery from Tommy John surgery following the 2019 playoffs. There are still a lot of things that have to go right, and Yankee fans should be wary of any setbacks, but it looks like the road is open to the team getting their All-Star shortstop back.

What can we expect from him when he does return to the team? Didi will have missed at least three months of live baseball, undergone reconstructive surgery on his throwing arm, and be asked to man the most important infield position on a team in the thick of a playoff hunt.

Fortunately we have two other players, both returning from the same surgery, both All-Star or better true talent players, to examine in the early goings of 2019. Shohei Ohtani has made his return to the Angels as a DH exclusively, while Corey Seager is back to being the starting shortstop for the Dodgers.

Neither have exactly blown the doors off in their first bits of action, with Ohtani at a 111 wRC+ and Seager with a 91 entering play last night. I wonder if there’s something deeper and more elemental to their performance that they share, and if so, can we then expect Didi to perform that way upon his return?

First off, their plate discipline is pretty much in line with what we’ve seen from both hitters so far in their careers. Seager is both walking and striking out a little bit more, but his 9.7% K-BB% is actually better than his career mark. That’s a positive step, but could really just indicate that teams in general are preaching better plate discipline in the era of three true outcome baseball.

So instead, we turn to Statcast, and this is where things start to get interesting, albeit divergent. Ohtani’s actually hitting the ball harder than last year, a sterling 95.6 average exit velocity. That’s better than what Aaron Judge produces over a full season. The problem, though, is that the ball’s not getting into the air, with an average launch angle of just 5 degrees. Ohtani’s GB/FB ratio has almost doubled in 2019, and in the era of the juiced ball, well, it’s not what you want.

Seager, meanwhile, is on the opposite end, with his launch angle almost doubling while his average exit velo falls to just under 88 mph, about league average. That’s led to him lifting soft fly balls that are easily converted to outs, and running a .294 xwOBA against his .303 wOBA, signaling that he really has “earned” his poor performance.

The key takeaway from both stars is that their swings are clearly inconsistent. Such a vast departure in quality of contact for both players, combined with the fact that Ohtani’s contact rate has dropped 3% and Seager’s has dropped 6%, show that neither are really comfortable at the plate yet.

While that’s to be expected during the first real baseball played in months, it’s some concern when you look at Didi. The key to Gregorius’ success as a hitter has been elevating the ball; he’s one of the biggest beneficiaries of the juiced ball and launch angle revolution.

This is every batted ball Didi has hit that drove in at least one run. He’s fairly adept at spraying the ball for singles, but when it comes to hitting balls for power, he’s all right field. He’s never hit a home run to the opposite field, and the reasoning for that should be fairly obvious. He’s a left handed hitter, at Yankee Stadium, who doesn’t hit the ball particularly hard. The trick then is to get the ball in the air to right field, and see what happens.

It’s that focus on fly balls and pulling the ball that’s taken Didi from a glove-first, bottom of the lineup hitter to the 120 wRC+ hitter we’ve seen and expect him to be. To hit like that, a pretty consistent swing is necessary:

Since joining the Yankees in 2016, you can see how consistently his batted balls perform. Almost all balls in play that have good results come in a pretty narrow band of both exit velocity and launch angle. That consistency has to be the Yankees’ biggest concern as we prepare for Didi’s return.

We’ve seen two great hitters struggle to keep their swings repeatable in their returns from Tommy John surgery. For Didi, that repetition is even more important since he has such a narrow band of batted ball outcomes. That is the thing the Yankees, and fans, need to keep the closest eye on as we all get ready for the starting shortstop to return.