Melbourne fullback Billy Slater concedes he is still overcoming a knee injury but insists the troublesome joint will stand up to the rigours of an NRL grand final.

Slater suffered ligament damage to his left knee during State of Origin II in Sydney on June 13.

His absence from the Storm side in the weeks that followed resulted in a significant downturn in their premiership fortunes as the one-time NRL frontrunners slumped to five successive losses.

The Melbourne custodian's return from the injury in round 21 helped to reinvigorate the club's premiership hopes.

He continues to take the field with his knee heavily strapped but said he has no concerns about the injury heading into the NRL decider.

"It's not an issue for me, I don't think about it leading into the game, I don't think about it during the game," Slater said at Thursday's grand final breakfast.

"It has been quite good, it's got better and better as the weeks have gone on, and I have played a fair bit of footy since I had the injury so it is just about managing it."

Slater was diagnosed with a grade two posterior cruciate ligament strain by Storm medical staff and missed five games.

Melbourne lost Slater's return match against St George Illawarra but since then they have won seven straight games to qualify for their fifth grand final in the last seven seasons.

The Australian No.1, who has starred in both of Melbourne's finals wins, said it was an injury that a number of NRL players have continued to play with.

"It was one of those injuries that happen in the tackle. It felt a little bit different, there was a little bit of pain there, I thought I was always going to miss a couple of weeks," he said.

"There are a lot of players in the NRL that haven't got PCLs (posterior cruciate ligaments), or the PCL doesn't function in their knees ... Paul Gallen, Justin Hodges, Sisa Waqa in our side doesn't have one, so you can get away without them.

"I don't know why we have them."

- AAP