Northampton were wrong to return George North to the field of play following a head injury against Leicester but have escaped any sanction, the Concussion Management Review Group (CMRG) has found.
North was injured in the first half of the Aviva Premiership clash on December 3 but despite appearing to have been knocked unconscious, he passed a head injury assessment and was allowed to resume by Saints' medical staff.
The CMRG set up to investigate the incident concluded that while there was "sufficient evidence" to end North's involvement in the match, the club did not "intentionally ignore the player's best interests".
George North will not play for Northampton again until he has been assessed by an independent expert in head injuries.
The Welsh wing, who has suffered a series of concussions, was cleared by Saints medics to continue playing during Saturday's Aviva Premiership clash with Leicester despite replays suggesting he had been knocked out following a tackle from Adam Thompstone.
Questions have been raised about whether the player's welfare was best served by his return to action but Northampton insist they were fully in compliance with World Rugby's head injury assessment protocols.
The club does admit, however, that the footage available to them at the time was limited and have taken the precautionary steps of withdrawing North from action pending the specialist's verdict.
George North will be out until the end of April after having further tests on a head injury.
The Welshman has now suffered three concussion in recent months and will spend some time on the sidelines.
Wales wing George North will not play for Northampton in Saturday's European Champions Cup quarter-final at Clermont Auvergne after his latest head injury.
North has been knocked unconscious three times in recent months, including in last Friday's 52-30 win over Wasps.
Winger George North says he's feeling OK after being knocked out during Northampton Saints' win over Wasps.
The Welshman suffered a knee to the head by Nathan Hughes, who was sent off for dangerous play but protested his innocence.
North was stretchered off unconscious and in a neck brace, but tweeted to say he was fine.
The Lions captain Sam Warburton has praised Australia for a "thrilling" test match in Brisbane.
"That was entertaining, that's for sure," he said in a pitch side interview with Sky Sports. "The last 20 minutes were so hard and we really had to dig in. Credit to Australia."
George North who scored a try in the first half has praised the travelling fans for "their fantastic support".