The NHL club issued a statement Saturday saying the 24-year-old underwent surgery for a depressed skull fracture and is expected to make a full recovery.
Geoffrion, playing for the Hamilton Bulldogs in a game held at the Bell Centre, was caught with his head down as he drove along the boards by Syracuse Crunch defenceman Jean-Philippe Cote in the first period.
Geoffrion was bleeding and holding his hands to his face when he skated off the ice to go to the dressing room.
Hamilton coach Sylvain Lefebvre said he believed Geoffrion was injured when he fell to the ice.
Cote was not penalized for his devastating but clean hit, though he did get a fighting major for scrapping with Bulldogs forward Mike Blunden, who came after him right after the hit.
Geoffrion had two goals in 13 games last season for the Canadiens.