Queensland star Kalyn Ponga has been ruled out of the Origin decider due to a calf injury, as reported by Fox Sports.
The Knights fullback underwent scans on Sunday morning and will miss the next two NRL matches.
He suffered the injury during the Maroos' 38-6 loss to New South Wales in Origin II.
After originally getting named to play in Newcastle's Round 15 clash, Ponga was a late scratch.
The Knights are hoping to get the 21-year old back for Round 18.
Origin III will take place at ANZ Stadium on July 10 with the series currently all tied up 1-1.