It isn't great news ahead of such an important game.
Ireland will be without six players for Friday night's key Group D clash with Wales in Dublin.
The FAI confirmed on Sunday night that Martin O'Neill's squad for the game had been reduced to 28 players, although Wes Hoolahan - who joined up with the squad despite coming off injured for Norwich at the weekend - remains in the panel.
A knee injury has ruled out Newcastle United defender Ciaran Clark, while Harry Arter of Bournemouth missed his side's 2-0 win over Swansea on Saturday with a calf complaint and did not travel.
The uncapped Reading midfielder Liam Kelly will have to wait for another opportunity to make his debut as he has a hamstring problem, with his clubmate Paul McShane also missing.
Goalkeeper Rob Elliott and Ipswich striker David McGoldrick both have knee problems and have been ruled out.
Robbie Brady is with the squad despite his suspension - he will be expected to start the friendly against Iceland on 28 March.
Republic of Ireland Squad to face Wales:
Goalkeepers: Darren Randolph, Keiren Westwood, Colin Doyle.
Defenders: Seamus Coleman, Cyrus Christie, Richard Keogh, Alex Pearce, John O'Shea, Andy Boyle, John Egan, Stephen Ward.
Midfielders: Aiden McGeady, Glenn Whelan, James McCarthy, Jeff Hendrick, Robbie Brady, Conor Hourihane, David Meyler, Eunan O'Kane, Wes Hoolahan, James McClean, Jonathan Hayes, Daryl Horgan, Callum O'Dowda.
Forwards: Jonathan Walters, Shane Long, Daryl Murphy, Kevin Doyle.
