Rieder suffered the injury in the second period of the Oilers’ win over the Montreal Canadiens Tuesday night. Rieder left the game and did not return.
After that game, coach Todd McLellan conceded that “when (an injury) happens that early, and a player doesn’t return, it’s never a good sign,” according to the Edmonton Sun.
Rieder has no goals and seven assists in 18 games so far this season.
The Oilers subsequently called up forward Patrick Russell from Bakersfield, who could make his NHL-debut this weekend when the team takes on the Calgary Flames and Vegas Golden Knights.