The veteran of 324 games will turn 36 on Thursday and accepts he can't expect to be a regular starter in Wayne Bennett's powerful squad.

But fresh from a quality playmaking performance for the Maori team in Saturday night's draw with the Indigenous All Stars, Marshall is confident he can still have a significant on-field impact.

"If I have to come off the bench and play a sort of a role through the middle, that's fine - a second hooker maybe or ball player, a bit like how (Queensland's) Michael Morgan plays Origin when he comes off the bench, that sort of role," said Marshall.

"I haven't really talked to Wayne about it."

He is ready to fight for a spot in the 17-man match-day squad week-in and week-out.

"Going to Souths I know...I won't be starting... but I have played long enough to put my best foot forward and I'll just prove a point that I should be picked every weekend," he said.

"Obviously the squad's very talented and I feel like I can add a lot to the squad and help with a few things there but playing is my number one priority."

South Sydney are among the pre-season favourites for the 2021 title, behind only Penrith, but Marshall sounded a note of caution.

"I'm feeling really confident for the season but competitions are hard to win mate, you have to put it together for 24 rounds."

Meanwhile South Sydney star Latrell Mitchell got through his first match since his hamstring injury in August, looking fit in a good performance for the Indigenous team.

"I just want to just back that performance up and build slowly," said Mitchell.

"I'm not in a rush to break records and whatnot but I really was happy with my performance tonight and I'll just go into next week and build from that...I'm sure Wayne's got a few tips."

Australian Associated Press