Ottawa Redblacks quarterback Drew Tate left the game in the second quarter of their 29-11 win over the Montreal Alouettes and did not return.
Head coach Rick Campbell said he will be evaluated more on Monday, but suspects the injury is to Tate's shoulder.
Tate was seen on the sideline in the second half wearing a sling.
Quarterback Ryan Lindley replaced Tate, going 7 of 14 for 76 yards and one interception.
With the win, the Redblacks moved to 5-7-1, good for first place in the East.