Boyd Cordner is confident one game can be enough to prove his form and fitness as he presses for selection in the New South Wales side for State of Origin III.

The Sydney Roosters back-rower returns from an ankle injury suffered in round 10 for Friday's NRL grand final rematch with Manly at Brookvale Oval.

The injury has sidelined the Kangaroos representative for both Origin fixtures so far this year, but with Anthony Watmough suspended for Game III on July 9 and Trent Merrin in doubt for the Blues, Cordner's return has come at a good time for coach Laurie Daley.

The match against the top-of-the-table Sea Eagles will be Cordner's only chance to impress before Daley announces his third Origin side early next week.

"I obviously hold some hope (of playing)," Cordner said on Wednesday.

"I need to get back and my focus is on the Roosters and playing well for them and getting the win on Friday night, so whatever comes out of that, whatever is meant to be is meant to be.

"I just have this game and a week in training, it is a different level altogether, obviously having a little bit of experience last year helps.

"I reckon I will be alright. I have trained really hard the last few weeks to maintain my fitness levels and try and be up there.

"I haven't lost any fitness."

Cordner, 22, made his New South Wales debut in Game III last year and has gone to win a premiership with the Roosters and play three Tests for the Kangaroos.

He said he had not yet heard from Daley and that it had been a bittersweet experience watching the Blues' series win.

"It was hard to watch but I am probably the biggest Blues fan and I was there throwing things at the TV, it was great to see them win," he said.

"To go up to Brisbane for game three and a chance of a whitewash I don't think many people would have believed NSW would have been in this position."

AAP