Defensive end Kevin Kwasny underwent surgery after he suffered a subdural hematoma — bleeding on the brain — at the CHUS hospital in Sherbrooke, a team spokesman said.
Kwasny was taken to hospital during halftime of the Gaiters' 25-18 loss to the Concordia Stingers on Saturday afternoon.
Team spokesman John Edwards said Kwasny, 21, showed no signs of injury during the game or as he left the field at halftime.
Near the end of the intermission, he was brought to the trainer's room by some teammates to be examined by a doctor. He was then sent to hospital in an ambulance.
Edwards added that even after looking at film of the game, coaches were unable to pinpoint any hit or play that caused an injury.
Kwasny's parents arrived from their home in Winnipeg on Sunday to be with their son.
The social sciences student is in his fourth year at Bishop's, and his third with the football team after missing one season with an injury.