Jeff Mathews was leading the Montreal Alouettes first-team offence at practice on Tuesday.
Starter Drew Willy left Saturday night’s game against the Saskatchewan Roughriders and didn’t return after being injured on a sack.
“I believe it was a neck and shoulder injury,” said Montreal head coach Mike Sherman after the game.
Willy was taken to the locker-room for medical treatment after being sacked in the third quarter by Riders defensive lineman Charleston Hughes. He was later seen back on the sidelines but was not dressed.
The 31-year-old was 8-of-15 for 157 yards and a touchdown when he left the game. Mathews replaced Willy at quarterback and went 8-of-12 passing for 98 yards as the Alouettes held on for a 23-17 victory.
The Alouettes take on the Ottawa Redblacks on Friday.
– with CP files