West Ham United defender Joey O'Brien has been forced to withdraw from the Republic of Ireland squad through injury.
The 28-year-old met up with his international teammates on Sunday, but he is now due to return to Upton Park after suffering a knee problem.
O'Brien has made five senior appearances for the Republic of Ireland since his debut in 2006.
Ireland welcome Oman to Dublin for a friendly on Wednesday before flying out to Georgia for their opening European Championship qualifier on Sunday.