REGINA — The Saskatchewan Roughriders clinched a home playoff berth for the first time in five years, but if they'll have quarterback Zach Collaros for the post-season remains to be seen.

Saskatchewan earned home-field advantage in the playoffs thanks to a 35-16 victory over the visiting B.C. Lions on Saturday. It was a dominant defensive effort by the Roughriders, but one that their starting quarterback watched from the locker-room for the final three quarters of the game.

Collaros was on the receiving end of a hard hit to the head from Lions defensive end Odell Willis late in the first quarter. Collaros delivered a pass on the run just before a charging Willis knocked him to the turf.

"He took a good shot. It was a headgear-to-headgear shot and for precautionary reasons our trainers thought it was best to take him out of the football game," said Riders head coach Chris Jones.

Collaros did not return. Brandon Bridge and David Watford split time under centre for the remainder of the contest. Collaros completed five of eight pass attempts for 52 yards.

The win also bumped Saskatchewan (12-6) into a tie with the Calgary Stampeders (12-5) for first place in the West Division. The Lions, having already clinched a playoff berth, are 9-8 and will cross over to the East Division for the post-season.

The Riders have a bye next week, while Calgary will visit the Lions in the final week of the regular season.

Zack Evans scored on a fumble recovery and Ed Gainey on an interception return that gave Saskatchewan 11 defensive touchdowns this season. It was Gainey's score early in the fourth quarter that put the Riders ahead 32-9.

"Our defence is very dynamic. We make a lot of plays," said defensive end Willie Jefferson. "We know that if the guys on the back end get a bad ball or if our linebackers get a bad ball it's because the defensive line has been making these quarterbacks run around and making them throw bad passes."

Lions quarterback Travis Lulay was ineffective and under duress most of the night. He was eventually pulled in the fourth quarter. Lulay finished 9 for 20 for 94 yards. He threw one touchdown — a 44-yard strike to Bryan Burnham in the third quarter — and two interceptions.

"You have to give Saskatchewan and their defence a lot of credit," Lions head coach Wally Buono said. "They didn't do anything too difficult, but they executed well and put pressure on the quarterback, stopped the running game and we couldn't get a thing going.

"We were out of sync (offensively). We threw the ball in the dirt, we threw the ball over heads. It was one of those bad nights... very disappointing."

Tre Mason scored Saskatchewan's lone offensive touchdown, a seven-yard run that put the home team ahead 13-0 in the second quarter.

Brett Lauther kicked four field goals for Saskatchewan and Cameron Marshall rushed 19 times for 134 yards. But it was the effort from the defence that has this team riding high going into the playoffs.

"We have been that standup defence all year," said Gainey. "As a defence, things happen sometimes, but at the end of the day. When you can score as many times as we did, you can't really say anything negative about that.

"The defence has been playing lights out all year and that's what we need going into the playoffs. Defence wins championships."

The Riders were without Collaros for four games early in the season after he suffered a concussion in Week 2. The team had a 2-2 record without their starter.