Ireland travel to Faro to take on Portugal at the Estádio Algarve on Wednesday, September 1 before returning to Ireland to take on Azerbaijan on Saturday, September 4 and Serbia on Tuesday, September 7 at the Aviva Stadium.
Enda Stevens, Callum O'Dowda, Jason Knight and Chiedozie Ogbene have all been ruled out through injury whilst West Bromwich Albion striker Callum Robinson tested positive for COVID-19 this week, and is currently in isolation.
Burnley defender Nathan Collins receives his first call-up to the senior squad whilst Jamie McGrath and Andrew Omobamidele keep their place in the squad after impressing in the summer camp in Andorra and Hungary.
Brighton and Hove Albion striker Aaron Connolly and Newcastle United midfielder Jeff Hendrick return to the squad having missed the summer international friendlies, with the squad set to fly out to Portugal on Sunday.
Republic of Ireland Squad
Goalkeepers: Caoimhin Kelleher (Liverpool), Gavin Bazunu (Portsmouth, on loan from Manchester City), Mark Travers (AFC Bournemouth)
Defenders: Seamus Coleman (Everton), Matt Doherty (Tottenham Hotspur), Shane Duffy (Brighton and Hove Albion), John Egan (Sheffield United), Dara O'Shea (West Bromwich Albion), Ryan Manning (Swansea City), James McClean (Wigan Athletic), Andrew Omobamidele (Norwich City), Nathan Collins (Burnley).
Midfielders: Josh Cullen (Anderlecht), Jeff Hendrick (Newcastle United), Conor Hourihane (Aston Villa), Harry Arter (Nottingham Forest), Jamie McGrath (St. Mirren), Jayson Molumby (Brighton and Hove Albion)
Attackers: Aaron Connolly (Brighton and Hove Albion), James Collins (Cardiff City), Daryl Horgan (Wycombe Wanderers), Adam Idah (Norwich City), Troy Parrott (MK Dons, on loan from Tottenham Hotspur), Shane Long (Southampton), Ronan Curtis (Portsmouth).
Fixtures
01/09 - Portugal v Republic of Ireland, Estádio Algarve, 7.45pm
04/09 - Republic of Ireland v Azerbaijan, Aviva Stadium, 5pm
07/09 - Republic of Ireland v Serbia, Aviva Stadium, 7.45pm
