Brisbane hooker Andrew McCullough will meet a surgeon later this week after scans confirmed he injured his medial collateral ligament (MCL) in training.
The Queensland State of Origin No.9 collapsed at training with the Broncos on Monday.
While initial concerns he'd damaged his anterior cruciate ligament (ACL) have been dismissed, the 29-year-old is facing at least a month on the sidelines.
If he has to undergo surgery it's expected the recovery time is likely to be even longer.
"He has had a scan today and he has got a fairly decent MCL injury so we will send him for a surgical opinion on that and go from there," Broncos head of performance Paul Devlin said.
"They tend to heal pretty well, he will go into as brace and we will progress his rehab journey straight away."
The news means McCullough is almost certain to be unavailable for the Maroons in the June 5 Origin opener at Suncorp Stadium.
It deepens an injury crisis for Queensland, especially at hooker, with Sydney Roosters' Jake Friend (biceps) already ruled out of this year's series.
Their absence has led to renewed calls for former captain Cameron Smith to be sent an SOS to come out of representative retirement.
Coach Kevin Walters has ruled out attempting to lure Smith to add to his 42-game Origin career however, stating North Queensland's Jake Granville is an option to make his Queensland debut.
"Granville is another who is still playing and seems to be on the way up - we will just have to look at our options," Walters told AAP on Monday.
