Donnacha Ryan will miss Ireland's autumn internationals and faces a race to be fit for the 2015 Six Nations.
A statement released by Ryan's Irish province Munster revealed that the lock must undergo toe surgery and will be out of action for four to six months.
The second row injured his right foot in a Pro12 game against Treviso in March and has been unable to rehabilitate the injury fully.
The injury caused him to miss Ireland's victorious 2014 Six Nations campaign.
The Tipperary-born forward failed to make an appearance despite forcing his way back into the training squads for the England and France games.
Munster's statement outlined that the decision to undergo surgery next week had been taken "following a consultation with a specialist in London" and after "extensive rehabilitation" had failed to completely cure the problem.
Ryan looks set to miss at least 10 rounds of Munster's Pro12 campaign, plus the pool stages of the Heineken Cup.
"Donnacha has done everything that has been asked of him and we know it has been a tough time for him with the option of surgery available as a last resort," said Munster Head Coach Anthony Foley.
"We are now at that point and we just want him to get through the next stage and back to full fitness."