Luke Keary's second concussion in five weeks will rule him out of an anticipated Origin debut, bringing James Maloney and Cody Walker into contention for the Blues vacant No.6 jumper.
Keary suffered a heavy head knock in the Roosters' 38-12 loss to Newcastle on Friday night and will require clearance from an independent neurologist before taking the field again.
With Brad Fittler picking his side on Sunday and return to play concussion protocols likely to keep Keary sidelined until Tuesday at the earliest, Blues advisor Greg Alexander told ABC Grandstand that the Roosters star is unlikely to be fit for game one on June 5.
"Luke's been in great form, he was part of the squad last year and Luke was looking like he was going to break into the team," Alexander said on Saturday.
"But I don't think Luke will take part, he won't be fit for game one."
With Nathan Cleary expected to reclaim the Blues No.7 jumper despite indifferent form for Penrith, South Sydney's Walker and incumbent Maloney now come into contention to partner the Panthers halfback.
Newcastle’s Mitchell Pearce has also been carrying a groin injury for the last weeks which flared up during Friday's upset of the premiers, ruling him out of training for the next week and scuppering any chance of a NSW recall.
Considered a near-formality for a long-awaited Origin debut before being knocked out against the Knights, NRL.com understands Keary was in good spirits and showing few ill effects from his latest concussion both after the match and on Saturday morning.
But under NRL rules, Keary's history of head knocks will now require independent clearance before he is able to play in any top flight game.
Any player diagnosed with two concussions in one season is required to be formally assessed by an independent doctor under NRL return to play rules.
NRL.com understands that both state organisations have agreed to implement the same rules to the Origin arena.
Keary, 27, sat out the Roosters' Anzac Day clash with St George Illawarra after being concussed a week earlier against Melbourne in round five.
He was also knocked out while playing for Australia last year and also suffered headaches for a few weeks because of a broken jaw picked up in the 2018 pre-season.
Walker will get one last chance to press his claims for a Blues call-up when he and fellow Origin hopeful Adam Reynolds lead the Rabbitohs against Wests Tigers on Saturday night.
A one-game suspension sidelined Maloney for Penrith's last-start win over Parramatta, but the veteran playmaker is available should Fittler plump for an experienced head in the halves.