Wales winger George North has been advised by a leading concussion expert to miss the rest of the season after he suffered his third head injury in two months.
North appeared to be knocked out during Northampton Saints' victory over Wasps on Friday night, but the club confirmed that he is fine and hope to have him available for their match with Clermont Auvergne on Saturday.
However, Professor Willie Stewart told the Daily Mail: "George needs to be given an extended rest period to figure out if this is something that he has just not recovered from or whether there are genuine issues.
"I think he personally needs to say, 'No, I'm not playing again this season'. If he does play again too soon it could be the end of his World Cup or even his career.
"The people looking after him, including Northampton and the Welsh Rugby Union, should be recommending some time out and the experts he is seeing should recommend some time out. No-one should be talking about playing him next week. That's just ridiculous."
North missed part of the Six Nations after he was knocked unconscious against England.
