Ireland's quest to win a first World Cup has suffered a major setback after Dan Leavy was ruled out of the tournament by a knee injury described by Leinster as "complex".
Leavy lasted only 11 minutes of Saturday's Champions Cup quarter-final victory over Ulster before he was carried from the pitch on a stretcher having replaced Sean O'Brien in the second-half.
The 24-year-old openside had just recovered from the long-term calf injury that forced him to miss the recent Six Nations in which Ireland surrendered their crown to Wales.
Not only will Leavy be absent for the climax to Leinster's bid to defend their European title, he will also sit out Japan 2019 to rehabilitate an injury that will require long-term medical attention.
Leinster Rugby can confirm that Dan Leavy had an initial scan yesterday on a complex knee ligament injury but needs further assessment this week. He has been ruled out for the remainder of the season and into next season to include the Rugby World Cup. pic.twitter.com/WoUPca6nRI— Leinster Rugby (@leinsterrugby) April 1, 2019
"Leinster can confirm that Dan Leavy had an initial scan yesterday on a complex knee ligament injury but needs further assessment this week," his province announced.
"He has been ruled out for the remainder of the season and into next season to include the World Cup."
Leavy was superb throughout last year's Six Nations as Ireland completed the Grand Slam, but has struggled with injury in the wake of the subsequent summer tour to Australia.
"Dan worked so hard to get himself back and physically fit," Leinster scrum coach John Fogarty said.
"He's such a huge threat on either side of the ball, gives the team a lot confidence so it's a big loss for Leinster and Irish rugby. He'll make a plan now to get himself back."
Meanwhile, Joey Carbery is set to be assessed by Munster's medical team later to determine the extent of the hamstring injury he suffered in Saturday's win at Edinburgh.
The Ireland out-half was forced off in the opening half at Murrayfield after feeling a 'tightness' in his left hamstring.
He is now a doubt for the Reds' trip to Saracens in the Heineken Champions Cup semis on April 20.
Flanker Jack O'Donoghue failed a HIA in the win against Edinburgh and he will now follow the return to play protocols.