Ireland and Leinster flanker Sean O'Brien is set to miss the rest of the season after an infection complicated his recovery from shoulder surgery.
O'Brien was ruled out of Irish coach Joe Schmidt's Six Nations plans after damaging his shoulder against Ulster in a Pro12 clash in late December.
The 27-year-old had hoped to return in time for Leinster's Heineken Cup quarter-final in Toulon in April.
But a post-op infection appears to have scuppered those plans.
The problem saw him lose almost a stone in weight and O'Brien looks certain to sit out Ireland's summer tour to Argentina in order to engage in an extensive pre-season programme.
The back-row forward committed his future to three-times Heineken Cup winners Leinster by signing a new two-year contract in January.
O'Brien, who was part of the Lions squad that toured Australia last year, had been linked with a move to France.
Newspaper reports suggested he was on the verge of joining European champions Toulon.