According to Adler, manager Aaron Boone said he is "unsure" whether Gregorius will be able to return this season following an MRI and cortisol treatment Sunday.
Gregorius, 28, has had a solid season for the Yankees, hitting .268 with 27 homers and 86 RBI from his shortstop position. He has now posted three straight seasons with at least 20 home runs and 70 RBI.
While he's generally been healthy in 2018, Gregorius did have a stint on the disabled list in late August with a left heel contusion.
"Obviously, Didi is so important to what we do, he's such an important player to us, the middle of our lineup, the middle of our field—he's kind of our quarterback out there," Boone said at the time, per Coley Harvey of ESPN.com. "He does so many things intangibly well that we certainly will miss him. But we also feel like we have the people capable of stepping up for him while he's down."
The Yankees have been hit with a spate of injuries late in the regular season, with Gregorius, Aroldis Chapman, Aaron Judge, Gary Sanchez and CC Sabathia all being forced to the disabled list simultaneously at one point.
In Gregorius' absence, the Yankees may be forced to shuffle their starting lineup. Gleyber Torres will likely transition to shortstop, while Neil Walker will likely split second base base duties with utility infielder Ronald Torreyes.