Duke freshman Mason Plumlee, a 6-10 center who was in line to start this season, will now instead be sidelined for an indefinite amount of time after breaking his left in practice on Wednesday.
The injury will not require surgery and will be evaluated weekly by the Duke medical staff.
"We are confident that he will make a full recovery," coach Mike Krzyzewski said in a statement. "Mason is going to be a very good player for us and we look forward to him getting healthy and returning to the court."
Plumlee is a McDonald's All-American who averaged 12 points, eight rebounds, three assists and three blocked shots in exhibition wins over Pfeiffer and Findlay.
Duke opens their regular season Friday night at 7 p.m. against UNC Greensboro.