Flanker Josh van der Flier will miss Ireland's tour of South Africa and Leinster's Pro12 semi-final against Ulster next Friday after ankle surgery.
Van der Flier, 23, sustained the injury against Treviso on Saturday and has been ruled out for eight weeks.
He saw a specialist on Monday and, following a further review, had an operation on Tuesday.
Ireland face South Africa in Cape Town on 11 June, followed by Tests in Johannesburg and Port Elizabeth.
Leinster full-back-back Rob Kearney (ankle) and fly-half Johnny Sexton (quad), who missed the weekend win over Treviso as a precaution, are "making good progress".