George North is set to miss Wales' entire autumn schedule after being ruled out for six to eight weeks with a knee injury.
The Northampton Saints wing sustained the issue during Sunday's 57-13 Champions Cup defeat to Saracens at Franklin's Gardens.
And the Premiership club confirmed on Tuesday that the 25-year-old had suffered a sprain to his posterior cruciate ligament, requiring up to two months' rehab.
The injury almost certainly makes North unavailable for all four of Wales' forthcoming Tests, including fixtures against Australia, New Zealand and South Africa.
INJURY UPDATE:-- Northampton Saints (@SaintsRugby) October 17, 2017
George North suffered a sprain to his posterior cruciate ligament against Saracens, which will require 6-8 weeks rehab pic.twitter.com/2cBXBtz7Au
British and Irish Lion North will also miss Northampton matches against the likes of Clermont Auvergne and Wasps during his time on the sidelines.
North's international future was secured on Monday by a change to Wales' selection policy that permits players holding more than 60 caps to play their domestic rugby outside the country.
The former Scarlets man has already racked up 69 appearances for his country.