Belfast - Ireland wing Tommy Bowe dealt a blow to his country's hopes of a third successive Six Nations title with the news he will be out for six months following a knee operation.
The 31-year-old -- scorer of 30 tries in his 67 Tests -- suffered a serious knee injury early on in Argentina's crushing 43-20 victory over the Irish in the World Cup quarter-final earlier this month.
"Tommy sustained posterior cruciate ligament and meniscal injuries to his right knee during the Rugby World Cup quarter-final against Argentina," Ulster Rugby said on Tuesday.
"He had successful surgery to repair the damage yesterday, and he will be ruled out for at least six months."
Bowe will probably be joined on the sidelines by Munster flanker Peter O'Mahony in being ruled out of the tournament as he also suffered knee ligament injuries in the 24-9 win over France in their final World Cup pool game.
Two other of Ulster's Ireland World Cup players will also take time to regain full fitness as lock Iain Henderson, who was one of their standout players at the tournament, will be sidelined for six weeks with a hand injury.
Centre Jared Payne, who missed all the action bar the opening win over Canada with a fractured foot, will be unavailable for an unknown period of time.
"Jared's fractured foot was stabilised through successful surgery," said Ulster Rugby in a statement.
"Ulster Rugby is awaiting his first post-operative review, after which a prognosis will be known."