Ireland flanker Tommy O'Donnell has been ruled out of next month's World Cup after suffering a dislocated hip against opening warm-up opponents Wales two days ago.
The 28-year-old Munster forward, who has won nine caps, was carried off during the second-half after producing an outstanding display as Ireland cruised to a 35-21 victory in Cardiff.
He spent Saturday night in hospital in the Welsh capital and subsequently underwent detailed medical checks.
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In a statement, the Irish Rugby Football Union said: " Investigations at University Hospital Wales yesterday afternoon confirmed that Tommy suffered a hip dislocation in the game against Wales.
"He will be limited to non-weight bearing activity for at least six weeks and has unfortunately been ruled out of participating in RWC15 (Rugby World Cup)."
O'Donnell's loss will be a blow to Ireland head coach Joe Schmidt as he prepares to continue the tournament build-up with further preparation fixtures against Scotland, Wales and England.
Ireland, the reigning RBS 6 Nations champions, will contest the same World Cup pool as France, Italy, Canada and Romania, with two teams securing quarter-final places.
The IRFU, meanwhile, said that wing Andrew Trimble will undergo "a precautionary scan" on the foot injury he suffered during the Wales match.