Melbourne plan to have star spine members Harry Grant and Ryan Papenhuyzen locked away long-term before any prospective south-east Queensland expansion bid can look to raid the premiers' roster.

The Storm's post-Cameron Smith era begins in Thursday's season-opener against South Sydney, with No.9 successor Grant watching from the sidelines due to an MCL strain.

Smith's retirement, and one last rebuff of the Broncos, leaves Brisbane with more than $500,000 to splash on their final two 2021 roster spots, while the Titans boast a similar figure and room for potentially one more mid-season signing.

Melbourne though are well aware of the threat posed by a potential second Brisbane expansion side, with any prospective NRL club to be locked in by July and begin recruiting for 2022 from the get-go.

Queenslanders Cameron Munster (signed until 2023) and Grant (mutual option for 2023) have both been publicly touted as marquee signing targets by Brisbane Jets spokesman Nick Livermore.

The breakout 2020 campaigns of Grant and Papenhuyzen (signed until 2022) has both in line for sizeable upgrades from their current contracts, with Storm officials discussing long-term offers internally.

Papenhuyzen's management is understood to be in Melbourne this week, with chairman Matt Tripp understanding the attraction the young playmakers hold for the Storm's 15 NRL rivals, and a potential 16th expansion club.

Papenhuyzen breaks through

"Harry, Paps all those younger guys that are coming off in 18 months' time, we want them here long-term," Tripp told NRL.com.

"It's clear they're the future of the club and make no mistake, we'll fight hard to keep them.

"If I was an expansion club I'd be saying who's the best talent out of contract as it stands right now, and that's who you go after.

"You want successful, quality players, it's as simple as that. No issue there at all.

"It's up to us to be prepared and ready, and hopefully have those guys bedded down by the time that rolls around. The wheels are in motion on a lot of those discussions right now.

"We're already thinking about what the list looks like next year and the year after. And we're acutely aware that some of our good players will be targeted.

"We'll combat that and be aiming to keep all that talent in our club. That will always be the plan, regardless of whether a Queensland side comes in or not."

The Storm kick off their campaign with a significant retention win last week in re-signing Jahrome Hughes until the end of 2024.

The Kiwi halfback knocked back a lucrative three-year Warriors deal in the process, while newly crowned co-captain Dale Finucane remains in talks around a post-2021 extension as well.

While Melbourne have long prepared for Smith's exit and shaped their salary cap accordingly, the Broncos and Titans both kept their powder dry to the tune of more than $500,000 on the chance of luring him north for an NRL swansong.

The debut gets better and better for Harry Grant

The Gold Coast remain on the hunt for another hooker having filled 29 of their top 30, but will also consider front-loading 2022 contracts to give free up more cap space for next season.

Brandon Smith remains a priority target for next year though his release from Melbourne is contingent on the Storm landing a quality replacement in return, a scenario Titans officials are privately growing pessimistic about.

The Broncos meanwhile have filled the 28 spots required by NRL rules and left two spots open until as late as August 1, when rosters must be finalised for the year.

Brisbane coach Kevin Walters said on Thursday he was in no rush to hit the market as he paid Smith a fond farewell from the NRL.

"We still have two spots. We have 28 filled and we still have two to shuffle around," Walters said.

"We will see what happens in the next month or six weeks, but we've got until August now haven't we?

Of Smith's retirement Walters added: "I'm relieved in two ways. One is that he has finished with a grand final win.

"That's a terrific achievement and as much as anyone in the game he deserves that honour.

"And the second thing he is not around to haunt the Broncos anymore.

"He did get away, but we can't have everyone play here in Queensland.

"I just think he is a great player, a terrific guy to work with and it's a shame we couldn't get him here in a Broncos jersey at some stage but I'm really happy for Cameron and his career.

"He is a great person, with a great family and now he can just relax and enjoy what this great sport brings to everyone."

Round 1 hype - Storm v Rabbitohs