Phillies believe Didi Gregorius will round back into form in second season after elbow surgery

In deciding to sign Didi Gregorius to the one-year, $14 million contract that was finalized Friday, the Phillies considered his eight-year body of work in the big leagues and a glowing recommendation from manager Joe Girardi.

But they also weighed a relevant question: Will Gregorius be the same player after elbow surgery 14 months ago?

If Gregorius were a pitcher, there would be little doubt. Ulnar collateral ligament reconstructions — known colloquially as “Tommy John surgery” — have become almost as common as dental visits for a generation of pitchers who typically return to the mound within 12 to 15 months of being branded on the inner elbow by a roughly 3-inch crescent scar.

But the club of shortstops — all position players, really — who have undergone the procedure is far smaller. Of the 487 players who had it during their big-league careers, only 10 were shortstops, according to data tracked by Hardball Times writer Jon Roegele. Yankees phenom Gleyber Torres is among those who had Tommy John surgery while in the minors.

It’s less straightforward, then, to predict how completely a shortstop might recover. Tony Womack, for instance, moved from shortstop to second base for the rest of his career after Tommy John surgery at age 34 in 2003. Rafael Furcal’s career all but ended after he had the surgery at age 35 in 2013. But Zack Cozart started an average of 116 games at shortstop and posted a .714 OPS over six seasons after undergoing the procedure at age 25 in 2011.

A one-year contract minimizes the Phillies’ risk with Gregorius. But they still did their homework, comparing his offensive metrics from last season with his successful 2017 and 2018 and studying the quality of his throws from shortstop once he rejoined the Yankees in June, seven months after surgery.

What they found, according to a source, was nothing to suggest that the 29-year-old (he will turn 30 in February) can't regain his status as a top-10 shortstop in baseball.

Gregorius, who will be introduced Monday with newly signed pitcher Zack Wheeler at a Citizens Bank Park news conference, batted .238 with 16 homers and a .718 OPS in 324 at-bats last season, his worst production since 2015. But his underlying metrics were consistent with the previous two seasons, when he received votes in the American League MVP balloting.

To wit: Gregorius’ percentages of hard-hit (34.8) and barreled (5.9) balls were actually higher than in 2018 (30.6 and 4.7). His average launch angle (17.2 degrees) was higher than 2018 (15.6) and comparable with 2017 (17.4), and his exit velocity (88.2 mph) was better than in both 2018 (86.5) and 2017 (84.4).

All those numbers suggest that he’s driving the ball with as much force as he did before the injury.

“Didi has been a great player for us,” Yankees manager Aaron Boone said at the winter meetings this week. “He’s a great person. I think, obviously going into a winter where he’s healthy, I would expect a really full, productive season from him.”

If anything, Gregorius might have been luckless last season. His batting average on balls in play was only .237, down from .259 in 2018 and .287 in 2017, though he did struggle with off-speed pitches (.319 slugging percentage compared with .494 and .578 in the previous two seasons).

Statistically, Gregorius’ defense slipped a bit, too. But the Phillies didn’t detect a weakening of his arm strength based on his throws. They’re confident he will represent an upgrade at shortstop over Jean Segura and Scott Kingery, who are slated to play on both sides of Gregorius next season.

Girardi’s scouting report from having managed Gregorius in New York from 2015 to 2017: “Left-handed bat. Power. Plays an outstanding shortstop. He can play second, as well. He’s a real character guy and a real hard worker that is a really important clubhouse presence. I’ve always been a big fan of Didi.”

Fourteen months after surgery, the Phillies didn’t find reason to believe anything has changed.