Ireland winger Keith Earls has been ruled out of the upcoming Six Nations campaign after Munster announced the extent of his knee injury on Thursday.
The 26-year-old is set to be sidelined for approximately six to eight weeks after sustaining medial ligament damage to his left knee during Munster's Heineken Cup clash with Edinburgh last week.
Earls was duot to join up with Ireland after the 38-6 victory but the injury meant he was unable to travel to Carton House.
"Keith, who signed a two year IRFU contract this week to stay with the province, underwent a scan on Monday before meeting with the specialist yesterday in Dublin where the injury prognosis was confirmed," read a Munster statement.
Earls is yet to feature under new boss Joe Schmidt after knee problems sidelined him from autumn Test series duty.
Former New Zealand schoolteacher Schmidt had hoped 39-cap Earls would beat his knee issues back in November, but his problems lingered on.
Fit by the end of November, just weeks after Ireland action finished, Earls had found form ahead of the Six Nations but once again injury has struck at the worst possible moment.
Schmidt had admitted at Wednesday's Six Nations launch the outlook on Earls was fairly bleak.
"I'd say there might be a bit of medial damage there," said Schmidt on Wednesday.
"If it is, it could be anything from three to six, to eight weeks.
"Certainly he'll be unavailable for the Scotland and Wales games."
The worst possible prognosis has now been realised, after Munster and the IRFU were able to examine detailed scans.
Ireland will aim to start the Six Nations with experienced centre pairing Gordon D'Arcy and Brian O'Driscoll in tandem against Scotland in Dublin on February 2.
Fit-again Craig Gilroy and Simon Zebo are in Irish Wolfhounds action against England Saxons in Gloucester on Saturday, and could yet prove their fitness to force a return to Schmidt's full Six Nations squad.