Coach Lindy Ruff declined to reveal the nature of the injury Tuesday but noted that Gerbe was ruled out after meeting with team doctors after he practiced Monday. Gerbe was initially hurt after being checked in the third period of a 4-2 win at New Jersey on Saturday.
Gerbe has one assist in five games since making his NHL debut after being called up from the minors on Dec. 6.
The Sabres, who host the Devils on Wednesday, will also be without defenseman and captain Craig Rivet, who will miss at least two weeks with a shoulder injury. Rivet returned to practice this week after missing two games but was ruled out after experiencing soreness in his shoulder.
Forward Patrick Kaleta has been cleared to return after missing seven games with a head and neck injury.