Northampton Saints will not allow winger George North to play again until he undergoes an independent medical assessment on the head injury he suffered against Leicester Tigers on Saturday.
The Wales international landed awkwardly after being tackled in the air by Leicester's Adam Thompstone and appeared to lose consciousness.
He was taken off the field for a head injury assessment by Northampton's medical staff before being allowed to return for the rest of the match.
The club released a statement on Tuesday defending the decision to allow North to play on, saying their medical staff did not have access to the full range of replay angles available to television audiences.
"The medical team can only base their decisions on the evidence available to them at the time of assessment," the club said on their website.
"George was fully assessed by the doctor away from the pitch using the established protocols and processes, and passed fit to return to play.
"As with all such injuries, if evidence suggesting a loss of consciousness had been available to the medical team at the time of assessment, George would not have been allowed to return to the field of play."
North, 24, struggled with concussion last season, suffering several blows to the head, one of which kept him out of action for five months.
"(Northampton) is referring George to an independent expert as part of the club's ongoing assessment process and George will be stood down from play until this process is complete," the club added.
Northampton, who were beaten 19-11 by Leicester, are ninth in the 12-team Premiership and next play Sale Sharks on 23 December.