Cameron Murray concedes he won't know if his body is ready for the rigours of State of Origin until after an NRL return from an ankle injury.
Murray will play his first game in a month for South Sydney against Parramatta, a day before NSW name their side for the June 9 Origin opener.
The 23-year-old started running again last week, and was considered only a "slight chance" by Wayne Bennett to play on Saturday.
But the NSW back row desperately needs him ready for Melbourne.
Angus Crichton will miss the opener because of suspension.
Crichton's Sydney Roosters teammate Victor Radley is out of contention to be picked for Game I and Game II after also being rubbed out.
Their Roosters skipper Boyd Cordner is also gone for the entire series, leaving a big hole on the left edge.
It means Frizell will likely start on the right, while Shaun Lane, Ryan Matterson, Isaah Yeo, Tariq Sims and Liam Martin are the Blues' other options.
Murray would be a certainty to be picked if fit, be it at lock, second-row or off the bench for the Melbourne game.
"We'll see on the weekend how I pull up and how the lungs are," Murray said.
"I haven't played for a couple of weeks and it seems like the game is getting faster each week.
"But I'm more than ready to face it and do my best for South Sydney."
Murray insisted Origin had not been on his mind when pushing for his return, given any longer layoff would likely have cruelled his Origin hopes.
But he does have unfinished business in the Origin arena.
Part of NSW's team that won the series in 2019, Murray was injured after just five minutes on the field in Game I last year and watched the Blues relinquish the Shield from afar.
"It was hard for me to watch and try to make a difference because I was sitting on the sidelines," he said.
"There is a little unfinished business there.
"We didn't play the best last year and I think we have the talent across the state to win a couple more Origin series over the next few years.
"That (unfinished business) will be a motivator for anyone who wears that Blue jersey."
Rabbitohs teammate Cody Walker claimed Origin was the furthest thing from his mind, given Souths' two 50-point thrashings in recent weeks.
"We're not performing as a team to even be credentialled to get a mention in a side like that," Walker admitted.
Jack Wighton and Jarome Luai remain favourites to claim Walker's No.6 NSW jersey if he is not selected.