Wales, Lions and Blues prop Gethin Jenkins will be out for around three months after a shoulder operation. It means that the 24-year-old, who started all three Lions Tests, will miss Wales' four autumn internationals and the opening Heineken Cup rounds.
Jenkins has had a long-standing shoulder problem, but the latest injury news comes as a surprise.
Fellow Lions Tom Shanklin, Gavin Henson and Shane Williams are all battling to be fit for Wales' November Tests.
Martyn Williams, Ryan Jones, Gareth Cooper and Ceri Sweeney are expected to return from injury soon.
Grand Slam champions Wales will need all their resources for a formidable series that sees them face New Zealand, Fiji, South Africa and Australia on successive weekends.
Ospreys loose-head Duncan Jones will be favourite to take Jenkins' Wales place, with the Blues' John Yapp also in contention.