Ireland's Denis Leamy faces four months on the sidelines as he prepares for shoulder surgery.
The Munster back rower will go under the knife next week, meaning he is expected to miss the start of his side's Heineken Cup campaign and Ireland's games against Canada, New Zealand and Argentina in November.
New Munster coach Tony McGahan revealed he is on the lookout for cover, but said: "We're not signing anyone for the sake of signing anyone - they need to fit the criteria that we are looking for."
The 2017 RBS 6 Nations was watched by record numbers of fans
29 March 2017, 12:25pm
After an enthralling RBS 6 Nations Championship of twists, turns, and no small amount of drama on the last day, figures show the RBS 6 Nations is going from strength to strength, year on year, with no sign of slowing down.