The status of Duke superstar Cooper Flagg is uncertain for the remainder of the ACC tournament after he suffered an ankle injury during a quarterfinal victory over Georgia Tech in Charlotte on Thursday.

Blue Devils coach Jon Scheyer told reporters post-game that Flagg had suffered a sprained ankle but no broken bones. Scheyer indicated it was too early to know how long Flagg might be out.

“He sprained his ankle,” Scheyer said. “X-rays were negative, which is great. We just have to understand that there’s going to be swelling, and see how he recovers and how we go from there.”

Duke is 29-3 this season and ranked No. 1 nationally. The Blue Devils are a lock for a No. 1 seed in the NCAA tournament and among the top contenders for the national title.

Flagg was injured with 2:46 remaining in the first half, when he appeared to land on the foot off Georgia Tech forward Baye Ndongo after coming down with a rebound. Flagg went to the Duke bench — punching a seat in frustration — before being helped to the locker room, riding much of the way in a wheelchair.

Flagg returned to the Duke bench without any sort of protective boot or brace on his injured leg. He did not return to the game.

Here’s video of the injury:

The 6-foot-9 Flagg was ACC Player of the Year as a freshman this season, averaging 19.4 points, 7.6 rebounds and 4.2 assists heading into the conference tournament. He will almost certainly be a first-team All-American, is among the top handful of candidates for the various national player of the year awards and is the presumptive No. 1 pick in the NBA draft if he turns pro.

In addition to Flagg, Duke also lost forward Maliq Brown to a shoulder injury in the second half. Scheyer said after the game that Brown — who averages 2.7 points and 4.1 rebounds this season off the bench — had dislocated his shoulder and was been treated at a local hospital.

Duke next plays Friday night, facing the North Carolina-Wake Forest winner in an ACC semifinal game.