Carter limped off and headed for the locker room after colliding with Buffalo defenseman Tyler Myers in front of the Sabres' net with 2:20 left in the first period Wednesday night. Philadelphia leads the series 2-1.
The Flyers called it a lower-body injury and said Carter might return.
Myers was also hurt on the play after Carter shouldered him across the jaw. Myers returned for the second period.
Carter led the Flyers with 36 goals and tied for third with 66 points in the regular season.