Kevin Walters has confirmed that Adam Reynolds has been ruled out of the Grand Final rematch, while another star player remains in doubt.

Before being ruled out of Round 3, the club disclosed that scans revealed he aggravated an MCL sprain that he carried into the game and was likely to be absent for one to three weeks.

Reynolds was clearly in discomfort late in the second half against the Rabbitohs on Thursday night and was eventually benched for the remainder of the contest.

Surprisingly, Walters has also confirmed that star prop Payne Haas is in doubt for the clash on Thursday against the Panthers after not training with the team on Sunday.

"Payne has been named but we are not 100 per cent sure he will be playing yet," Walters said, via AAP, at a press conference on Sunday.

"He has still got a bit of a problem with his knee. He's had some scans and there wasn't too much there, but ... he is still not right to go at this stage.

"Reyno won't be playing and won't be named. He is out."

In Reynolds' place, Jock Madden is likely to enter the team, while Xavier Willison will be on standby if Haas is unavailable for the blockbuster match.

Madden played in five games for the club last season after joining from the Wests Tigers and has spent the start of this year in the QLD Cup.

"Every time Jock has had an opportunity he has played really well for us, so we expect no different on Thursday night in Penrith," Walters added.

"It is a great opportunity for Jock to showcase his skills. He is a different player to Reyno but an equally important member of the team.

"He is still maturing and we have a lot of confidence in him and the skillset he brings to the club."