Brisbane hooker Andrew McCullough has sent an injury scare through the Brisbane camp after suffering damage to his right knee during a training drill.
The Maroons rake was running the ball towards a teammate in an opposed session and then reeled out of the tackle in agony.
He was assisted from the training field by Broncos medicos to have treatment.
McCullough had an ACL injury to his left knee in the latter stages of 2017 but recovered in time to start the 2018 season.
Broncos officials were unsure of the extent of the latest injury.
McCullough will go for scans on Tuesday as Monday is a public holiday in Queensland.
An injury to their hooker is the last thing the Broncos need after their 2-6 start to the season heading into Friday's Magic Round clash with Manly at Suncorp Stadium.
Jake Turpin is the likely replacement for McCullough if he is ruled out.
The 22-year-old played two NRL games for Brisbane last year and has been lining up this season for Redcliffe in the Intrust Super Cup.
He is highly regarded for his running game, speed and guile out of dummy half and Brisbane captain Darius Boyd said he would do the job if McCullough was ruled out.
"Fingers crossed Macca isn’t too bad and doesn’t miss too many games but if he does we have a good replacement. I’d say Jake Turpin will play there," Boyd told NRL.com.
"Jake's played for us a couple of times and done a great job.
"He is not Macca but we don’t need him to be Macca. We just need him to be himself. He defends well and has good ball skills, and a good dummy on him as well."
Turpin impressed in the trial against Souths-Logan where he scored a try and showed excellent game awareness.
"I think that if Jake was at any other club he’d be a starter in the first-grade side,” Boyd said.
"Macca is the incumbent Queensland hooker and hardly ever misses a game of footy, so it is hard when you are behind someone who is always playing first grade.
"We are just very lucky to have Jake at our club and if Macca isn’t there he will do the job, and a good one I'm sure."
James Roberts and Jamayne Isaako were training with the club's reserves on Monday, indicating their positions in the backs are under threat from Gehamat Shibasaki and Kotoni Staggs.
Staggs trained at left centre and Shibasaki at right wing with the main squad.