Leinster's Garry Ringrose has been ruled out until at least November after undergoing an operation on a shoulder injury last Monday.
The centre initially suffered the injury during Leinster’s Pro12 semi-final defeat to Scarlets and recently posted a picture of himself in a sling on social media.
Despite the injury, he took part in Ireland’s summer tour of the USA and Japan, scoring two tries and a conversion during the three matches.
It's a further setback for Leo Cullen after Robbie Henshaw was recently ruled out for four months.
Ringrose will now miss most of Leinster’s Champions Cup pool games and Ireland’s November internationals against South Africa, Fiji and Argentina.
Henshaw will miss a similar period of time after he suffered a major pectoral muscle injury during the Lions 31-31 draw with the Hurricanes a fortnight ago.
Lions medical chief Dr Eanna Falvey said at the time that Henshaw had torn the muscle off the bone and said: “The muscle needs to be reattached, and that’s usually about a 16-week recovery.
“He may do slightly better, but that’s probably what we’re looking at.”
Leinster and Cullen are also bracing themselves for more possible bad news when the results of Sean O’Brien’s and Johnny Sexton’s scans come through.
The pair suffered injuries in the Lions drawn series finale with the All Blacks on Saturday and both are due to undergo scans on Monday before the players fly home on Tuesday.
Sexton injured his ankle in the first half of the game and also successfully underwent a HIA at one stage, while O'Brien was replaced at half-time as a result of damage to his shoulder following a hit from Jerome Kaino.
