All Blacks captain Sam Cane has been sidelined by concussion for the Chiefs' Super Rugby Pacific clash against Fijian Drua on Friday.
Cane, 31, left the field late for a head injury check during his team's win over the Hurricanes last week and is listed unavailable through injury six days later. Newshub understands that injury is concussion-related.
The openside flanker has been in career-best form this season, leading the unbeaten Chiefs to the top of the competition table midway through the regular season, but this latest setback is worrying, given his history of head injuries.
In 2019, Cane recalled a game where he was concussed against the Crusaders.
"We went to a lineout and Brodie Retallick made the call," he told Stuff. "I went up to him and said, 'what's that play?'
"He said, 'you know the one'… it was a special play that involved me and one we'd been practising all week.
"Apparently, I said to him, 'I don't know it, talk me through it'. At that point, he knew I wasn't quite right, and was no good to him or the team, and was also putting myself at risk by carrying on playing.
"He let the physio know, and they pulled me off then and there."
In 2020, as former players launched legal action against World Rugby, and the England and Wales rugby unions, Cane said he was concerned about the ongoing risk of concussion on his future health.
The former players alleged they had not been protected from that threat during their careers.
"Because of some of the knocks I’ve had, it always worries you," he said. "There's always the potential for that [concussion] and it could be just around the corner, it’s just one of the risks we accept playing this game.
"I can speak truly when I say I’ve never felt pressure to play through a head knock.
"I think were particularly well looked after here in New Zealand and even hearing stories from guys in other parts of the world, it would seem that New Zealand is leading the way in player welfare, even just with the resting of players."
In 2021, as Cane returned from a season-long shoulder injury for the All Blacks' northern hemisphere tour, former NZ captain Wayne Shelford expressed concern over his injury record.
"He is always probably one injury away from retirement from rugby, especially if it's to the head," Shelford told Newstalk ZB.
"He's had a lot of concussions in his career and if he gets another one, that could be the end of his career quite easily."
Cane also missed the All Blacks' Bledisloe Cup win over Australia at Eden Park last year with concussion, after colliding with teammate David Havili nine days earlier at Melbourne.