Shane Long and Derrick Williams have been ruled out of Republic of Ireland's upcoming international friendly against Northern Ireland and next week's Nations Cup game in Denmark.
The Southampton striker has an ankle injury while Blackburn defender Williams is suffering from a hamstring problem.
New call-ups Caoimhin Kelleher and Michael Obafemi have retained their place in Martin O'Neill's slimmed down squad.
Having missed last month's games against Denmark and Wales due to a foot injury, captain Seamus Coleman is determined to get the Boys in Green back on track.
"We want two good performances, two positive results," said Coleman.
"We haven't been at our best and we've not really had a strong 11 in consecutive games, as such.
"So it's about us going there and putting on a performance for ourselves, for the manager and for the fans as well."
Manchester United defender Lee O'Connor, who is captain of the Ireland Under-19s, will link up with the squad for training.
Aston Villa midfielder Glenn Whelan will lead the Ireland team out as captain against Northern Ireland but will not travel with the squad to Aarhus for the Denmark game.
The team will face Northern Ireland in the Aviva Stadium on November 15 and take on Denmark in Ceres Park, Aarhus on November 19.
Republic of Ireland Squad
Darren Randolph, Colin Doyle, Caoimhin Kelleher
Seamus Coleman, Cyrus Christie, Matt Doherty, Richard Keogh, Shane Duffy, Kevin Long, John Egan, Darragh Lenihan, Lee O'Connor*, Enda Stevens
Robbie Brady, Jeff Hendrick, Glenn Whelan, Conor Hourihane, Harry Arter, David Meyler, Shaun Williams, Alan Browne, Callum O'Dowda, James McClean
Scott Hogan, Sean Maguire, Callum Robinson, Aiden O'Brien, Ronan Curtis, Michael Obafemi