Coach Roy Williams made the announcement after the No. 10 Tar Heels' 97-73 rout of NC State on Wednesday night in Raleigh, North Carolina.
"He'll have surgery early next week, and he's probably done for the season," Williams said. "He hurt his knee. It's a crazy thing -- not an ACL or anything like that.
"But when you look at four to six weeks at this point in the year, it's basically the end of the season."
Williams is averaging 6.2 points, 3.3 rebounds and 2.2 assists this season.