John Egan, Alan Browne and Sean Maguire have been ruled out of the Republic of Ireland's UEFA Nations League game with Denmark on Monday due to injury.
Sheffield United defender Egan suffered a calf injury during Thursday's goalless draw with Northern Ireland, while Maguire lasted just 12 minutes after coming on a substitute due to a hamstring problem.
Maguire's Preston team-mate Browne is also out of the trip to Aarhus with a shoulder injury.
Ireland manager Martin O'Neill is already without the suspended James McClean and fellow midfielder Glenn Whelan.
He has given Hearts defender Jimmy Dunne his first senior call-up, while Manchester United's Lee O'Connor is also included after impressing during training.
Denmark vs Rep Ire
November 19, 2018, 7:30pm
Republic of Ireland squad
Goalkeepers: Darren Randolph, Colin Doyle, Caoimhin Kelleher.
Defenders: Seamus Coleman, Cyrus Christie, Richard Keogh, Shane Duffy, Kevin Long, Darragh Lenihan, Jimmy Dunne, Lee O'Connor, Enda Stevens.
Midfielders: Robbie Brady, Jeff Hendrick, Conor Hourihane, Harry Arter, David Meyler, Shaun Williams, Callum O'Dowda.
Forwards: Scott Hogan, Callum Robinson, Aiden O'Brien, Ronan Curtis, Michael Obafemi.