The 22-year-old had to be replaced just 10 minutes into the 12-6 defeat to England at the Aviva Stadium on Sunday and Irish coach Declan Kidney says the Munster wing will undergo surgery on Monday to correct the problem.
Kidney is also sweating over the fitness of Jonathan Sexton after the fly-half pulled up midway through the first half with a hamstring injury.
Ireland expect the Leinster star to be out for two weeks but won't discover the true extend of the problem until Tuesday as they wait to see whether Sexton will be fit to face Scotland in a fortnight.
"It looks like a couple of weeks for Jonny, but it would be wrong to try to second-guess the outcome. We'll know more by Tuesday," said Kidney after his team's first defeat of the tournament.
"It's been an additional couple of games and we had a few injuries leading into the tournament, but that's the way it goes."
Ireland are also assessing the injuries picked up by Sean O'Brien, Mike McCarthy, Brian O'Driscoll and Donnacha Ryan, although none of the quartet have been ruled out of action at this point.