DURHAM, N.C. -- Duke freshman sensation Zion Williamson was forced out of Wednesday night's game against rival North Carolina after just 36 seconds with what Blue Devils coach Mike Krzyzewski called a "mild knee sprain."
Williamson grabbed his right knee in pain after slipping awkwardly and falling when his left Nike basketball shoe fell apart as he planted hard while dribbling near the free throw line on the opening play. The blue rubber sole ripped loose from the white shoe from the heel to the toes along the outside edge, with Williamson's foot coming all the way through the large gap.
He walked off with a slight limp but under his own power before heading back to the locker room with no shoes on his feet.
"I was right there and I didn't really see what happened," said fellow Duke freshman Tre Jones, who was next to Williamson on the court at the time of the injury. "I just thought he'd twisted his ankle or his knee. But when he took his shoes off, I thought maybe something else was going on."
After the game, an 88-72 Blue Devils loss, Krzyzewski said that Williamson's knee was stable and that a timetable for his return would be determined Thursday.
Former President Barack Obama, sitting along the baseline near the Duke bench, shouted out encouragement to Williamson as he left the court.
Duke is four years into a 12-year deal with Nike as the exclusive supplier of uniforms, shoes and apparel. The private school didn't disclose terms of the 2015 contract extension. Nike has had an exclusive deal with the university since 1992.
Coach K: Zion has a 'mild knee sprain'
Mike Krzyzewski doesn't know the timetable after Zion Williamson's knee injury and laments losing another big player early in a Duke loss.
"We are obviously concerned and want to wish Zion a speedy recovery," Nike said in a statement. "The quality and performance of our products are of utmost importance. While this is an isolated occurrence, we are working to identify the issue."
Duke looked lost without Williamson. Meanwhile, North Carolina took advantage of the Zion-sized hole in the lane, scoring 32 of its first 34 points in the paint and finishing with a 62-28 scoring advantage there. The Tar Heels never trailed, pushed their lead to 22 with about 16 minutes left and held on.
"It put everyone in the position of having to figure it out, playing without him, while playing a really good team. It's not a good situation," Krzyzewski said. "At halftime the realization that he's not there settled in. And we played horrible to start the second half. The final 16 minutes I thought we played really well, but it was too late."
Williamson, the ACC's second-leading scorer at 22.4 points per game, has established himself as arguably the most exciting player in college basketball with his array of dunks and once-in-a-generation athleticism.
"It was the first time we've not played with him all season," Duke freshman forward Cam Reddish said. "We miss him as a player, but it's not just that. He is also the source of our energy. So, without him on the floor, that energy is missing. We have to be back in the gym tomorrow, figuring out how to find that energy while he is gone. However long that is going to be."
Duke next plays Saturday at No. 18 Syracuse (6 p.m. ET on ESPN).
ESPN's Nick DePaula and The Associated Press contributed to this report.