CHARLOTTE – Just when Duke started to arrive in the ACC tournament, its star player exited.

Cooper Flagg twisted his left ankle while pulling down a rebound and left Duke’s 78-70 win against Georgia Tech in a quarterfinal game of the ACC tournament on Thursday at Spectrum Center.

"Cooper ... sprained his ankle. X-rays are negative," coach Jon Scheyer said. "We just have to understand there's going to be swelling and see how he recovers and how he goes from there."

Duke's third-year coach added that it would be "a longshot" for Flagg to return this weekend. Top-seeded Duke will play the winner of Thursday's quarterfinal game between North Carolina and Wake Forest.

Flagg skied for a defensive rebound and landed hard, his legs coming out from under him. Replays showed that he didn’t land on another player’s foot; rather, he twisted his left ankle.

That came after the latest impressive sequence for Flagg and at a time when Duke (29-3) needed it; the Blue Devils trailed by 14 earlier in the first half, and on the defensive possession before Flagg’s injury, he had a vicious block high on the backboard that led to a 3-pointer by Isaiah Evans — Duke’s first after a 0-for-13 start.

After the injury and just before halftime, Flagg was helped back to Duke’s locker room by Neal Begovich and Stanley Borden. He did not appear to be putting any weight on his injured ankle.

A wheelchair was used to take Flagg to an X-ray room during halftime. He remained in the building and at the first media timeout of the second half, he rejoined Duke on the bench.

The freshman stayed on the end of Duke’s bench for the second half, close to Duke’s medical staff but not receiving attention.

Flagg hasn’t missed a game this season. He is the ACC player of the year and rookie of the year.