Life without Billy Slater was once a nightmare prospect for Melbourne.

But Storm assistant Adam O’Brien says it “won’t be the end of the world” if the veteran fullback misses the start of the NRL season.

Melbourne are hopeful off-contract Slater can finally overcome a second straight shoulder reconstruction this season.

The 33-year-old – restricted to just eight games in two years – told the Nine Network on Thursday night that he could not guarantee his NRL return.

But O’Brien said Cameron Munster’s form and livewire half Brodie Croft’s emergence ensured they would not be losing sleep over Slater’s return.

“If Bill is not there it won’t be the end of the world or our season,” he said.

“We haven’t made a decision on Billy for round one.

“If he is not there then we have a couple of options – we will just take it as it comes.”

Munster filled in spectacularly last season, helping Melbourne make the grand final.

But he will audition for the five-eighth role vacated by Blake Green (Manly) in Melbourne’s trial against New Zealand Warriors at Sunshine Coast Stadium on Saturday.

O’Brien admitted they were no closer to deciding whether to hand Munster the No.6 or No.1 jersey in 2017.

Not that he thought it made a difference.

“We’ve changed the way we play the six role to probably suit Cameron so I don’t think the difference between one and six is as great as the past,” O’Brien said.

“Whether he plays one or six, his role won’t change that much.

“What won’t be a headache is that he will be in the 13.”

Auckland Nines sensation Croft will chime in at halfback for Melbourne on Saturday.

But Storm captain Cameron Smith hinted that Croft could be wearing the No.6 jersey alongside mentor Cooper Cronk in the Storm’s season-opener against the Bulldogs next month.

“He’s played one NRL game during Origin for us and went really well at Auckland Nines so I am keen to see how he backs up,” Smith said.

“He is a chance to play round one if Billy is not right.

“Hopefully he takes that opportunity.”

Smith declared several starting spots were “up for grabs” on Saturday.

Four grand final team members departed in the off-season – Green, Ben Hampton (Cowboys), Kevin Proctor (Titans) and Marika Koroibete (rugby).