Scans have confirmed Kalyn Ponga has suffered a calf strain, possibly ruling him out of State of Origin III for Queensland.
Queensland star Kalyn Ponga is in doubt for the State of Origin decider after being ruled out for two weeks by his NRL club.
Ponga was a late scratching from Newcastle's win over Brisbane on Saturday after he sustained a calf injury playing for the Maroons in game two.
And the Knights on Sunday revealed that scans confirmed a calf strain.
"Ponga picked up the injury during State of Origin week and sat out the Knights' 26-12 win over Brisbane as a result," the Knights said in a statement.
"He is expected to miss the next two weeks."
Game three will be played at ANZ Stadium in 10 days' time, however, it remains to be seen whether Ponga will attempt to speed his recovery in time to play.
His possible absence will be a major blow for a Maroons side still reeling from their belting by the Blues in Perth, which set up a blockbuster decider.
Ponga was arguably Queensland's best in their game-one triumph but was quiet in their game-two defeat.
Maroons centre Michael Morgan is expected to lead a number of candidates to play at fullback should Ponga be ruled out.
Shifting Cameron Munster from five-eighth is another option, as is promoting utility Moses Mbye from the bench.
Brisbane's Anthony Milford, who returned to fullback in Saturday's loss to Newcastle, is another who can be brought in from outside the squad.
The Maroons name their team on Monday.
Front-rower Jarrod Wallace is widely tipped to be axed and be replaced by Brisbane's Joe Ofahengaue after his return from injury this week.
Speaking before the Ponga news, skipper Daly Cherry-Evans said he is licking his lips at the prospect of bouncing back and lifting the shield in enemy territory.
"I'm certainly super excited about what lies ahead for Queensland. We're playing in the decider, it's bloody exciting," Cherry-Evans said.
"I can't wait for it."
History shows Cherry-Evans is right to be excited about the Maroons' chances.
There have been six Origin game three deciders played in Sydney with the Maroons winning three and NSW two.
An 18-all draw in 2002 was as good as a victory for the Queensland, who walked away with the Origin shield by virtue of being the defending champions.
LIKELY QUEENSLAND TEAM: Kalyn Ponga, Corey Oates, Michael Morgan, Will Chambers, Dane Gagai, Cameron Munster, Daly Cherry-Evans (capt), Dylan Napa, Ben Hunt, Josh Papalii, Felise Kaufusi, Matt Gillett, Josh McGuire. Bench: Moses Mbye, Joe Ofahengaue, David Fifita, Tim Glasby.