Wing George North will miss Wales' four tests in November and December after hurting his left knee last weekend.
North will be out for a minimum of six weeks, his Northampton club said on Tuesday, three days after he was injured in a tackle by Saracens' Brad Barritt while playing for Northampton in the European Champions Cup.
The club said he sprained the posterior cruciate ligament, and will be out for six to eight weeks.
Wales has tests on successive Saturdays from Nov. 11 in Cardiff against Australia, Georgia, New Zealand, and South Africa.
He has 72 international caps but his recent career has been blighted by concussions, and he limped out of successive tours of New Zealand with Wales in 2016 and the British and Irish Lions this year, with hamstring injuries.