Ireland defender Darren O'Dea has returned to his club after being ruled out of Tuesday night's Euro 2012 qualifier against Andorra through injury.
The 23-year-old Ipswich player last week underwent a scan on a knee injury, which revealed a slight sprain, and although he was included in the party which flew out to Yerevan last Wednesday, he did not make the 18 for the 1-0 victory over Armenia.
O'Dea was able to train at Gannon Park in Malahide on Sunday, but has since been withdrawn and has gone back to Ipswich for treatment.
He becomes the fourth member of the squad to pull out, following Damien Duff, Keith Andrews and Keith Treacy on to the sidelines.
A fifth casualty, Paul McShane, is back in training after recovering from the hamstring problem which prevented his participation in Armenia.