Duke freshman star Cooper Flagg was helped off the court with a sprained left ankle late in the first half of the No. 1 Blue Devils' ACC tournament quarterfinal victory against Georgia Tech on Thursday.
Flagg, who was seen being taken to the X-ray room in a wheelchair at halftime, walked back to the bench under his own power -- without a boot -- early in the second half, but he did not return to the 78-70 victory.
X-rays were negative, but Duke said there was a lot of swelling in the ankle.
The Blue Devils also lost Maliq Brown in the first half after he again dislocated his right shoulder. He was taken to the hospital.
The top-ranked Blue Devils were trailing 26-17 late in the first half when Flagg went up for an uncontested rebound and crashed to the floor after his left foot appeared to land on the foot of Georgia Tech's Darrion Sutton.
Flagg, the ACC's player of the year and newcomer of the year, hobbled back to the bench in clear distress, then bent over with his hands on the seats and pounded a chair with his right fist.
After sitting on the bench for a few minutes, Flagg got up, put his arms around two teammates and was taken to the locker room for observation.
The 6-foot-9 Brown is a key reserve and versatile defender who is viewed as a vital cog in Duke's championship hopes. He had returned against North Carolina last weekend after missing about three weeks with a shoulder injury.
Duke was projected as the likely No. 1 overall seed in the NCAA tournament coming into the game after taking over the top spot in the rankings this week. The Blue Devils had won eight straight games before the ACC tournament.
Flagg averaged 19.4 points, 7.6 rebounds and 4.2 assists for the Blue Devils (28-3) during the regular season.
The Associated Press contributed to this report.