Wales No.8 Taulupe Faletau will miss the autumn internationals due to a knee injury.
The British & Irish Lions back-rower suffered the injury on his debut in the Aviva Premiership for Bath at the start of September, but was hoping to make a relatively swift recovery in time for the upcoming internationals.
However, interim head coach Rob Howley won't be able to select the key figure in the pack for the games against Australia, Argentina, Japan and South Africa in November.
Bath claim they do not expect the 25-year-old to even begin training with the rest of the first team until the middle of next month, which leaves little hope of competing at Test level for his country.
Wales will be hoping to have Faletau injury-free when they begin their Six Nations campaign in Rome against Italy on February 5.