Melbourne skipper Cameron Smith says the vacant Storm five-eighth role remains dependent on the return from injury of Billy Slater.
After the departure of Blake Green to Manly, Cameron Munster is the first choice to wear the No.6 jersey and has been named there for their final trial against the Bulldogs on Saturday in Hobart. Young Tonumaipea will start at fullback.
But Smith says Munster is likely to return to fullback to cover for Slater should the 33-year-old not be ready for round one, after his second shoulder reconstruction.
Another Queensland youngster Brodie Croft, who impressed in their trial win over the Warriors, could then partner Cooper Cronk in the halves or the Storm may leave Tonumaipea at the back.
"We haven't really locked anyone into any position for round one given there's a little bit of uncertainty around Bill and what that looks like if he's not in our team," Smith told AAP.
"Cam will be our five-eighth if Bill is playing but if he's not there that raises a few question marks as who goes where and really what sort of make-up gives us out most competitive team."
Slater was left out of Melbourne's final trial but Smith said that didn't mean he wouldn't be a starter in the Storm's opening round clash, also against the Bulldogs on March 3.
"I don't think Bill even knows but he's doing everything that every other player is doing, including contact," said Smith.
Slater reinjured his shoulder in round one last year after initial surgery in 2015.
"He's getting tackled, making tackles; it's not like he's restricted but we're not putting any pressure on him at all to be back for the first game.
"It's really when he feels he'll be right to go to play his very best for us."
Smith was named in the 24-man squad to travel to Hobart but said he wasn't a certain starter after only returning to training four weeks ago after the Four Nations tournament and the grand final loss to Cronulla.
Golden Boot award winner Cronk, as well as Kiwi Test representatives Jesse Bromwich and Tohu Harris will also make their first appearance of the year.
