The 6-foot-11 Drummond is averaging 7.3 points and 7.5 rebounds this season. He was selected to participate in the Rising Stars Challenge as part of All-Star Weekend later this month.
Drummond does not need surgery, and team doctors anticipate a full recovery with rest and rehabilitation.
Duncan was out on the court shooting about two hours before Friday's game, but he's been bothered by a sore left knee. Ginobili has left hamstring tightness.