Williamson is the No. 3 recruit in the country according to 247 Sports and committed to Duke.
Late in the second half of the exhibition game, Williamson, who is committed to Duke, was backing down North Carolina commit Nassir Little when he pulled the ball back out to the three-point line and looked to drive to the basket.
As Williamson attacked the hole, Little knocked the ball away, and as Williamson lost control, he landed awkwardly on his right hand.
The left-handed product from Spartanburg Day School in South Carolina did not return to the game.
Williamson has become a viral sensation thanks his highlight dunks that have left many eagerly awaiting for his college basketball debut. He won the McDonald's dunk contest Monday night and was joined by fellow Duke commits Cameron Reddish (No. 1 recruit according to 247 Sports), R.J. Barrett (No. 2 recruit according to 247 Sports) and Tre Jones (No. 9 recruit according to 247 Sports) at the All-American game.
Jeff Goodman of ESPN.com reports Williamson will see his personal orthopedist Thursday.