John O'Shea has withdrawn from the Republic of Ireland squad for Tuesday's Euro 2012 qualifier against Russia due to injury.
The Sunderland defender has been forced to miss the trip to Moscow because of calf and hip strains.
A statement from the FAI read: "The Football Association of Ireland today confirmed that following medical examination, John O'Shea has been declared unfit to take part in Tuesday's Euro 2012 qualifier against Russia.
"John was suffering from a calf and hip strain and will return to his club later this evening."
O'Shea's absence is the latest blow to hit Republic boss Giovanni Trapattoni with the Italian facing up to an injury crisis ahead of the crucial qualifier.
Shay Given is undergoing a scan on the back problem, while Aiden McGeady and frontman Kevin Doyle are struggling for full match fitness after lengthy lay-offs and Sean St Ledger is ruled out through suspension.
Republic of Ireland assistant boss Marco Tardelli is hopeful Given will be able to play despite his back injury.
Asked about Given's fitness, Tardelli said: "I don't know. He is with the doctors having a scan, but I expect him to play if he can."
Ireland head into the game knowing defeat is simply not an option if they are to keep alive their hopes of automatic qualification from Group B with Russia having established a two-point lead over them as a result of their 1-0 victory over Macedonia on Friday.
However, while the Republic's performance in a disappointing 0-0 draw with Slovakia has been widely criticised, Tardelli insists the spirit and belief remains high within the camp.
"We played against a very tough team - their world ranking is 10 places before us and they are in the same position as us in the table," added Tardelli.
"The result was not very, very good for us, but we played in the second half very well. We missed three or four good opportunities and I think it is possible to go to Russia and play to win."