REGINA — The Saskatchewan Roughriders will be without quarterback Zach Collaros for the foreseeable future.

The team placed Collaros on the six-game injured list Tuesday, five days after he left Saskatchewan's Week 2 game against the Ottawa Redblacks with a head injury.

The 29-year-old Collaros was 4-of-10 passing for 106 yards with a touchdown and two interceptions before he was hurt in the Roughriders' 40-17 loss last Thursday. He underwent concussion protocol after leaving the game.

"You don't ever mess around when it's a concussion-type situation," head coach Chris Jones said. "The league has the protocol that they go through and that's what we'll adhere to."

Collaros was acquired from the Hamilton Tiger-Cats this off-season. He was 18-of-25 passing for 203 yards and one touchdown in the Riders' season-opening 27-19 win over Toronto.

Collaros missed three games with a head injury in 2016 and was sidelined two years earlier due to a concussion.

Jones announced that Canadian Brandon Bridge will start at quarterback when the Roughriders host the Montreal Alouettes on Saturday night.

Bridge completed 13-of-22 passes for 145 yards and an interception after Collaros left last week's game.

"He played OK. He did some good things and there were some plays I'm sure he and I would both want back," Jones said. "You can't just pinpoint one area. There's a lot of improving that needs to go on."