Munster and Ireland lock Donnacha Ryan has been ruled out for 10 weeks due to a knee ligament injury.
Ryan sustained the injury during Munster's victory over Gloucester last weekend in the Heineken Cup.
The 29-year-old strained the ligaments in his left knee and was replaced by CJ Stander with 10 minutes remaining.
Ryan is expected to be out for approximately 10 weeks, forcing him out of Ireland's autumn internationals against Samoa, Australia and New Zealand respectively.
Munster hope that the Tipperary native will return to training in time to play a role in their final two Heineken Cup matches in January.