Spartak Moscow winger McGeady was named in the provisional squad but has withdrawn with a foot injury and will be replaced by Chelsea's young midfielder Conor Clifford.
Birmingham midfielder Fahey is suffering with flu and his place will be taken by Millwall's Andy Keogh, who has scored three goals in his last five matches for the Championship side.
Wolves defender Stephen Ward is also doubtful due to a knee injury and will be assessed by medical staff, while Darren O' Dea, John O'Shea and Shane Long sat out training due to fatigue.
Captain Robbie Keane is missing as he opted to remain with his LA Galaxy side and manager Giovanni Trapattoni will look at other forward options.
Norwich midfielder Wes Hoolahan is targeting his second cap and is likely to be given a run out by the Italian.
Republic of Ireland squad: Westwood (Sunderland), Forde (Millwall), Randolph (Motherwell), Coleman (Everton), O'Shea (Sunderland), O'Dea (Toronto), Kelly (Fulham), McShane (Hull), Ward (Wolves), Clark (Aston Villa), Andrews (Bolton), McCarthy (Wigan), Clifford (Chelsea), Meyler (Sunderland), Whelan (Stoke), Keogh (Millwall, McClean (Sunderland), Brady (Man Utd/on loan at Hull City), Hoolahan (Norwich), Doyle (Wolves), Cox (Nottm Forest), Walters (Stoke), Long (West Brom).
Stand-by: Duffy (Everton), Delaney (Crystal Palace)