The injury was examined by Duke's medical staff after the seventh-ranked Blue Devils flew home to Durham, N.C., Wednesday night following their hard fought 78-67 ACC victory at Maryland.
Smith collided with Maryland's Dave Neal on a screen early in the second half, went to the bench, and later exited without returning.
"Nolan's condition improved overnight, but we are going to proceed cautiously," Coach Mike Krzyzewski said on the school's Web site. "Our medical staff will continue to monitor his progress and he will return to the rotation when he is fully healthy. Nolan is an important part of this team and we are looking forward to his return."
Smith, a 6-foot-2 inch native of Upper Marlboro, Md., is averaging 8.5 points and 2.3 rebounds in 28 games this season (21 starts).