David Klemmer is out of Friday night's clash against the Sydney Roosters after revealing he played for more than 20 minutes against the Melbourne Storm last weekend in a daze because no one knew he'd been concussed.
Remarkably, the Knights prop was left totally confused and disorientated following a head clash in his first hit-up of the game that wasn't picked up by anyone at the ground before he put his own hand up to be replaced.
He has subsequently failed to pass a series of concussion protocols with his place on the bench going to Jack Johns.
Klemmer himself was oblivious to what happened against the Storm and continued playing, making 14 tackles and a further three carries of the footy before leaving the field 23 minutes in. He subsequently failed a HIA and did not return.

"I think I got a whack on the chin in my first run of the game," Klemmer told the Newcastle Herald.
"I can remember that hit-up but according to my stats, I had another three runs and made 14 tackles and I can't remember any of them. I do remember Melbourne scoring a try and I must have come to a bit and I was thinking how the hell did I get here.
"I had no idea where I was but I was out there playing. I wasn't knocked out but I was running around and I was apparently talking in tackles and screaming. It's all pretty bizarre."
Klemmer said the Knights trainers were alerted to the fact something was wrong with the big prop when he asked to come off.
"Normally, if a trainer comes on to take me off for an interchange, I'm normally arguing with them to stay on because I never want to come off," he said.
"In this case, apparently I asked to come off. Lou [Knights physio Lou Cutler] told me I told her I was no good and needed to come off.
"They knew something was wrong with me when that happened. Lou was worried because she knows what I'm like normally."
Klemmer has since watched the game back on video and says he can tell all was not right with him.
"I've looked back at the vision and I definitely wasn't myself moving around out there," he said. "Like I said, I don't remember doing anything out there.
"When I woke up the next morning after the game, I felt like I'd had a big night out and was hungover. I felt a bit crook but as the day went on, I started to feel a lot better."
While the Knights have both Origin prop Daniel Saifiti and middle forward Jesse Sue returning from injury, the potential loss of Klemmer would make the task of beating the Roosters that little bit more difficult.
But Knights co-captain Jayden Brailey is confident his side can rebound from a shocking performance against Melbourne and inflict a rare defeat on the Roosters, who have won 13 of the past 15 games between the two sides.
"We have to respond and I'm sure we will," Brailey said. "We definitely need a good, confident start - we have spoken about that. That's been one of our biggest issues all season - letting opposition teams get the jump on us.
"It's going to be about getting the errors out of our game and applying some early pressure because that's the area where we have been letting ourselves down."