Roosters skipper Boyd Cordner sidelined despite passing concussion test

Australian captain Boyd Cordner won't play for the Sydney Roosters this weekend, despite passing all the concussion protocols in the leadup to the match.

Cordner suffered a head knock in last week's win over Newcastle, his second serious knock of the season.

He missed six weeks after being concussed against Melbourne in Round 8.

Earlier this week it was revealed Cordner took no further part in the match against the Knights after the club doctor raised concerns about his mental health.

Cordner's cousin, Joel Dark, died last week after suffering a head knock in a game in Newcastle.

"Boyd's been great. I know a lot of people have talked about it this week and the concern is there and we understand that - which is right - but he's been great," coach Trent Robinson said.

"Physically, post-game, he's trained well this week. But he won't play this weekend. That decision was made a few days ago."

Robinson said the decision was made in consultation with the club's medical staff

"It was a discussion between the doctor, myself and Boyd," he said. "We knew what Boyd wanted to do but the doctor and myself spoke on Sunday and then spoke again on Wednesday and made that decision.

"We think it's right and it's been our protocol for a while now. We will continue to work towards that.

"He left it to us. We had to tell him what we thought from both our points of view and he accepted that.

"He will continue to train and get ready for next week."

The Roosters play the Sharks tomorrow night, with a win guaranteeing the club a top-four spot as they seek a third consecutive premiership.