OTTAWA — The Saskatchewan Roughriders lost starting quarterback Zach Collaros early in their game against the Ottawa Redblacks on Thursday night.

Collaros, who was sacked in the first quarter, took a number of big hits including one by Avery Ellis, which appeared to be the one that forced him to leave the game in the second quarter.

Collaros was 4 for 10 for 106 yards, one touchdown and two interceptions when he left.

He was replaced at QB by Brandon Bridge.

TSN's Matthew Scianitti reported that Roughriders head coach Chris Jones said Collaros underwent concussion protocol and will be re-evaluated in the coming days. 

Losing Collaros for any length of time would be difficult for the Roughriders.

In their season opening victory against Toronto last week Collaros was 18 for 25 for 203 yards and one touchdown.

Collaros joined the Roughriders in the off-season after playing the past four seasons in Hamilton.