NSW enforcer Payne Haas is racing the clock to overcome an ankle injury for the third State of Origin match, while an ongoing sternum issue will prevent Campbell Graham being considered for a Blues debut.
On the Queensland front, coach Billy Slater has doubled down on keeping Kalyn Ponga off the team sheet despite Reece Walsh's suspension as his Maroons look to complete a series clean sweep of the Blues.
Both sides are to be named on Monday for the July 12 finale at Sydney's Accor Stadium.
The Blues' best player in their game-two loss, Haas aggravated a lingering ankle problem during the second half of Brisbane's NRL win over the Dolphins on Saturday night but managed to finish the game.
The Broncos do not believe the issue is severe, but concede it was bad enough that Haas felt the need to tell medical staff post-match.
The club will wait until Monday to make further assessments of the issue. Blues coach Brad Fittler said he had yet to determine the prop's availability.
"He's had an ankle injury for a while now, a few weeks," Fittler told the Sunday Footy Show.
"I'm just getting feedback right now.
"We'll see how that is, the severity of that."
Haas tweaked his ankle in camp for Origin I, though has not missed any game time since.
He would be a big loss for the Blues. He was leading the Dally M rankings when voting went behind closed doors in round 12 and fellow props Tevita Pangai Jr. and Stefano Utoikamanu failed to fire in the opening two Origin matches.
In career-best form, South Sydney centre Graham was NSW's 18th man for the series opener but withdrew from camp with a sternum issue he has battled all season.
With Latrell Mitchell and Tom Trbojevic sidelined by injury, Graham was considered a serious chance to earn a debut in the NSW centres for game three.
Souths coach Jason Demetriou rested Graham for Friday night's defeat of the Warriors and said he would do the same for the match against Canterbury on July 8.
The Rabbitohs told AAP it would be up to the Blues whether Graham was selected for the Origin game but Fittler confirmed on Sunday he wouldn't be.
"Campbell won't be considered," Fittler said.
"I don't believe he'll be playing for a couple of weeks for the Bunnies,"
The injury leaves Bulldogs co-captain Matt Burton the front-runner to snare a spot in the centres.
Burton appeared in two matches of last year's series and would also provide utility value to a Blues side that was forced to play hooker Damien Cook at centre when Trbojevic went down in Origin II.
After Broncos speedster Walsh beat him to play fullback for Origin I, Ponga ruled himself out of the series to focus on his Newcastle duties following two long concussion lay-offs in the past year.
Walsh's three-game, contrary-conduct suspension has rubbed him out of Origin III but Slater said that hadn't impacted his position on selecting Ponga.
"The priority for Kalyn is just to keep on the field and do his job for the Knights," Slater told The Sunday Footy Show.
"That decision was made pretty early that Kalyn wouldn't come back for this third game.
"I've got no doubt that he's going to represent Queensland again in the future."
Gold Coast's AJ Brimson and incumbent centre Hamiso Tabuai-Fidow are jostling for the chance to replace Walsh at fullback.