Dejected Panthers players.

Slumping Panthers braced for week of soul-searching

Penrith players can expect a confronting "honest review" of their slipshod 18-10 loss to Manly as they bid to arrest a mid-season slump endangering their shock rise as premiership contenders in 2018.

The Sea Eagles' upset follows on the back of a 32-6 last-start loss to the Roosters, book-ending last week's Rep Round with the Panthers' two worst performances of the season.

With a NSW Origin trio of James Maloney, Nathan Cleary and Tyrone Peachey set to go back into camp this week and stars Josh Mansour (cheek) and Reagan Campbell-Gillard (jaw) still sidelined, Friday's clash with fellow upstarts the Warriors shapes as a crucial clash as both sides come off losses.

"Today was a poor performance for us as a club, it's not what we pride ourselves on," coach Anthony Griffin said.

"We need to get together and regroup, believe in ourselves and play better than what we did today.

"We've just got to have a really honest review and I think next week in a way, we'll have a group of guys that are together the whole week, it'll be an uninterrupted week.

"I think that'll be a good thing for us even though we're missing our Origin players. We'll regroup and we'll be better."

Cleary's sin-binning for shoving opposite number Daly Cherry-Evans in pursuit of a grubber late in the match proved pivotal, with Manly taking a 12-10 lead from the resulting penalty.

Trent Hodkinson's match-winning try came shortly after with Penrith reduced to 12 men, but Griffin had no issue with the decision to bin his star halfback or the youngster's role in the play.

"There wasn't much in it but we put ourselves in that position," Griffin said of Cleary's professional foul.

"That's just the way they're refereeing the game at the moment.

"He was just doing his job there and I thought the call was consistent with what's been happening. I don't think it had anything to do with Nathan in particular, or playing Origin. It was just a play in the game."

In better news for Penrith, the team's medical staff have cleared boom back-rower Viliame Kikau of any structural damage in his knee after copping a hefty knock from the head of Manly rookie Manase Fainu.

Kikau will be assessed throughout the week as he recovers from what is hoped to be just a bad cork that will not rule him out of the Warriors fixture.

Griffin is also optimistic that Waqa Blake (ankle) and Corey Harawira-Naera (groin) will be available for next week's game.