The 26-year-old joined the Easter Road club on a three-year deal from Preston North End earlier this month and has been an instant success in green-and-white, scoring the winner in a Betfred Cup tie against Ross County before putting in an impressive display last weekend against Aberdeen.
Horgan has been capped four times by Ireland in the past and made no secret of his desire to force his way back into Martin O’Neill’s plans after finding game-time limited at Deepdale.
Hearts back-up goalkeeper Colin Doyle has also been named in the squad. The 33-year-old - also capped four times by his country – has yet to play a competitive match for the Jambos since signing from Bradford due to the form of Zdenek Zlamal.
Ireland play Wales in Cardiff on Thursday, September 6 in the UEFA Nations League before travelling to Poland on Tuesday, September 11 for a friendly.