Sydney Roosters halfback Luke Keary has been ruled out of Saturday night's clash with Parramatta because of the head knock suffered against Melbourne.
Keary left the field in visible pain against the Storm last weekend and did not return.
While able to train with his Roosters teammates on Thursday, Keary's concussion history has given medical staff reason to be cautious.
Keary suffered five head knocks between 2018 and 2019, causing him to miss five NRL games and consult with a specialist.
"He got through training quite well but it just wasn't quite enough to have him play tomorrow night," Roosters coach Trent Robinson said.
"This happens weekly in our game so we understand it. How we deal with it post-concussion varies depending on individuals."
Robinson said the Roosters were proud of their culture around concussion, with superstars Boyd Cordner and Jake Friend enjoying the club's full support when they chose to hang up their boots due to repeated head knocks.
"It's really simple. Let the process take its course and support the player," he said.
"They want to know that they're cared for and they'll be cared for.
"You've just got to have the right system in place and moral compass about the way that you handle it."
Robinson said he had no reason as yet to fear that concussion could force Keary into retirement.
"He trained quite well yesterday and he's in good spirits," he said.
"He's recovered quite quickly but just not enough to play on Saturday."
Every NRL side has next weekend off for the representative round so Keary will have at least three weeks to recover from his first head knock since 2019.
Sam Walker looks likely to switch to halfback, where he played in Keary's absence last season, for the Eels game.
Robinson was coy as to who would partner him in the halves but Drew Hutchison, Lachlan Lam, Adam Keighran and Joey Manu are options.
Meanwhile, Robinson has endorsed club star Daniel Tupou who is under pressure to retain his Origin spot for NSW given the form of Canterbury winger Josh Addo-Carr.
Tupou replaced Addo-Carr for the first game and performed strongly but 'The Foxx' has scored five tries in two NRL appearances since being snubbed.
Robinson said debate around selection was only natural.
"It creates interest," he said. "(NSW) has some decisions to make but I think we all saw how (Tupou) played in that game."
Robinson added New Zealand international prop Jared Waerea-Hargreaves was moving closer to returning from his hamstring injury.
"He had a good run on Thursday," Robinson said. "His progress is going well but obviously not well enough to play."
