The Melbourne Storm are understood to be resigned to the fact Cameron Munster won't play in the club's Round 1 clash against the Penrith Panthers on Friday evening.

The five-eighth missed both trial matches for the Storm during the pre-season as he recovered from a pre-season injury.

It was revealed earlier in the week that Munster would be touch and go for the match, with the star revealing he had re-aggravated the injury by slipping in the shower which ruled him out of Melbourne's second trial in Fiji against the Newcastle Knights.

"I was looking good for the Fiji game, and then I slipped in the shower, so it wasn't ideal," Munster said.

"It's a frustrating injury, but I'm doing everything I can to get it right. I tried to do a little bit today, but I need to be 80 to 100 per cent to be able to play on Friday."

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The five-eighth has continued at an attempt to play on Friday evening, but Channel 9s Nat Yoanndis is reporting Munster trained away from the main group during the club's captain's run on Thursday morning.

Players not training at full fitness during the training run is usually a tell-tale sign they will not play the following day.

Coach Craig Bellamy told reports per AAP that Munster is unlikely to play.

"We don't think he's going to play," Bellamy said.

"It's disappointing for us and for Cameron, as he's done everything asked of him but it hasn't got good enough for him to play."

Bellamy confirmed that both Jonah Pezet and Tyran Wishart were the options to replace Munster. Wishart has been named as the utility on the bench, while Pezet is in the squad as a back-up option.

Pezet, rated as one of the best young halves in the game, has played both trials at five-eighth for the Storm and has spent time at first-grade level previously replacing both Munster and halfback Jahrome Hughes.

Melbourne head into the clash aiming to keep their historic Round 1 victory record alive, while the Panthers will be out to bounce back from a World Club Challenge defeat a fortnight ago in England.

Kick-off is set for 8:05pm (AEDT) with teams to be trimmed to 19 players 24 hours before kick-off.