Grand Slam Irish full back Rob Kearney will miss Leinster's Heineken Cup semi-final shoot-out with Munster at Croke Park on Saturday.
The British & Irish Lions tourist picked up mumps last week and has been unable to train properly for the past 10 days, leaving Leinster coach Michael Cheika with no option other than to leave him on the sidelines.
"Rob's not going to make it. Even if he was to get himself out on the field he has had no training behind him for the last 10 days, so we wouldn't even consider it," said Cheika.
"He had to go to hospital because he had quite a high fever, but he's ok now. He has recovered well and the doctors have really looked after him well and he's in good spirits too.
"The priority for him is to become healthy again and for us to get him back on the field as soon as we can. It's times like this that you're happy to have the kind of squad that we have with top quality players."
Another 2009 Lions tourist, Luke Fitzgerald is among the candidates to take over the No 15 jersey for the 'Battle of Ireland', although it is likely that he will remain on the wing with the veteran Girvan Dempsey coming into the back line.
Cheika is more hopeful of getting Springbok scrum ace CJ van der Linde back into his side for the weekend and the prop will undergo a fitness test on Tuesday.
"CJ has been back in training this week and he'll undergo his full fitness test on Tuesday to show us how capable he is of playing. But we'd be confident that he'll get past that and, if he does, then we'll have to see how he fits into the squad," added Cheika.
Leinster are bidding for their first Heineken Cup final and are hoping it will be fourth time lucky at the semi-final stage having fallen at the penultimate hurdle in 1996, 2003 and 2006.
Croke Park will be filled to overflowing for the clash with the reigning champions and Munster will be looking for a repeat of their emphatic 30-6 triumph at the same stage three years ago at Lansdowne Road on their way to their first title.
"A berth in the Heineken Cup final makes the game so big. As defending champions, Munster probably see it as their place to be," said Cheika.
"We've had to fight really hard to make it here. They have been pretty untouchable so far this year - quite commanding in the Pool stages and they are also doing well in the Magners League.
"We understand that not many people expect us to beat them, but it's all about us believing in ourselves."
"We've had a pretty consistent feeling about our 22 and we know that in a game of this type all 22 players, or a good part of them, will make a good contribution to the performance."
The directors of ERC voted unanimously at a Board meeting to postpone all decisions including the release of further instalments of ERC's distributable central revenues to the six shareholder countries until 19 February next when the Board will meet again to reconsider the issue.