Cooper Johns is set to join the casualty list for Round 1 at the Melbourne Storm after suffering a shoulder injury during Sunday's trial with the Newcastle Knights.

Johns, who started the game and was set to play in place of Cameron Munster - who is suspended - during the opening round of the season, lasted just three minutes after suffering a shoulder injury in a Jake Clifford tackle.

He didn't return to the contest, with the Storm eventually confirming it was an AC joint problem.

Johns was seen in a sling after the game, with Cameron Munster confirming to Fox League that he was not in a good way.

“It didn’t look good, he is in a sling at the moment, so it is a 50/50 call," Munster said.

While the club will wait for scans to be taken on Monday, the chances of Johns running out in Round 1 for Melbourne when they take on the Wests Tigers looks slim.

It'll mean Johns joins Cameron Munster, Brandon Smith and Harry Grant as certain spine players missing, while Ryan Papenhuyzen is also only a 50-50 chance of playing as he recovers from his own injury, with Storm football operations manager Ryan Hoffman telling Fox League he is still quite ginger.

“Look it is going to be touch and go with Paps (Papenhuyzen), I saw him running yesterday he is still quite a bit ginger,” Hoffman said.

“I’d like to give him a 50/50 chance at this stage and hopefully we can work some magic in the next two weeks before Round 1.”

MELBOURNE, AUSTRALIA - MARCH 11: Ryan Papenhuyzen of the Storm thanks the crowd after winning the round one NRL match between the Melbourne Storm and the South Sydney Rabbitohs at AAMI Park, on March 11, 2021, in Melbourne, Australia. (Photo by Robert Cianflone/Getty Images)

While Tyran Wishart has thrown his hand up for the number nine jumper on the back of two excellent trial performances for Melbourne, the other positions in the starting spine outside of Jahrome Hughes are up for grabs.

In Johns' absence, Jonah Pezet and Jayden Nikorima could well come into contention for a spot in the halves, although Nick Meaney also spent some time there in Sunday's trial and could be considered by Bellamy.

That would likely require Papenhuyzen to be fit though, given the depth at fullback is skinny for the men in purple.

Xavier Coates is another concern for the Storm after he suffered a head knock during last night's game, but with two weeks to pass HIA protocols, he should be suiting up for the season-opener.