Northampton and Wales winger George North will take a month off from rugby after suffering a fourth head injury in five months.
The 22-year-old was knocked unconscious by Nathan Hughes in the 52-30 win over Wasps and was seen by a neurosurgeon on 1 April to discover the extent of his injuries following a succession of head blows.
North was twice knocked out during Wales' Six Nations defeat to England and also missed the autumn Test against South Africa after suffering a blow while playing against New Zealand.
"We have listened to the advice we sought and George will be taking some time away from the field," said director of rugby Jim Mallinder.
"Throughout this process it is important that George's welfare comes first and that he is treated patiently and calmly, only returning to action when all of the medical team are happy for him to do so."
Wales were reprimanded by World Rugby for failing to follow concussion protocols during the match at the Millennium Stadium, when medics failed to spot the second head blow suffered by North in the second half.
Already ruled out of the European Champions Cup quarter-final against Clermont Auvergne, North will miss the semi-final of the competition on 18 or 19 April should Saints prevail, while he will also be absent for the Premiership games against Exeter Chiefs and Saracens.