Brodie Croft was knocked out cold at Broncos training on Tuesday just as he was on the cusp of taking his place back in the starting side to play the Eels.
Croft, who was set to replace Sean O’Sullivan in the halves, trained with the main group before he collided with the hip of a teammate.
He was on the ground for several minutes as the team huddled around him and is set to miss the clash at Bankwest Stadium on Friday night.
"I just spoke to him and he has a bit of a sore head at the moment," said captain Alex Glenn.
"I think his head collided with one of the boys’ hips and his head got caught up in the wrong position. He is recovering at the moment the best he can and has to have the rest of the afternoon off to recover, and then he has to see medical staff and doctor in the morning."
Croft injured at training
With such a short turnaround the chances of Croft playing on Friday are negligible. The 23-year-old was dropped after the round 16 loss to the Roosters so the injury has stalled his comeback
"It was a pretty nasty blow," Glenn said.
"He was looking forward to putting the jersey back on and doing the players and his family proud so he is disappointed to go down.
"We want to make sure that his health is the main priority because we have all seen what can happen long-term if you don’t treat these head knocks with seriousness and the effects they can have in the long run."
The Broncos last played a NSW-based side on September 3 against Penrith and due to the COVID-19 restrictions have a window of opportunity outside of the “bubble” later this week.
Chace Haas, the brother of Payne Haas, died last month and the Broncos want to give their star prop forward time to be with his family. Haas, who trained with the reserves on Tuesday, will miss the Eels clash.
"This Friday we get six hours out of the bubble. Payne has had a lot going on with his family and we want him to have an opportunity to be with his family out of the bubble," Glenn said.
"Payne has had an outstanding year, he has turned up every week for our team and put his body on the line and he deserves the opportunity to go home and see his family for the first time in a long time."
Passion driving Glenn to play on
The Broncos, in 15th position and in the midst of a nine-game losing streak, return to the venue where they suffered a humiliating 58-0 loss in the first week of the finals last year.
"It was a very long time ago now, we have touched on it several times. It's in the back of our minds but it's behind us now," Glenn said.
"We just want to put in a decent performance. We have two more games and we want to finish the season strong.
"I know it won't be an easy task but I have full faith in our boys if we play to our strengths and build pressure that we can give them on a run for their money.
"They are a bit down on confidence and lacking some attack, so we are hitting them at the right time."