David Kearney, who was on the bench last year, is included along with James Coughlan, another player drafted into the squad last term without playing, and first-timer Jack McGrath.
At the weekend Donnacha Ryan (knee) and Iain Henderson (toe) joined an injury list which already includes Stephen Ferris, Richardt Strauss, Tommy O'Donnell, Jordi Murphy and Simon Zebo.
"The squad combines players who have shown form in the domestic season mixed with those who have a proven record at international level," Schmidt said in a statement on Wednesday.
"As always there were some very difficult decisions. Some players have had limited opportunity to impress due to injury and others have performed very well and it was difficult to leave them out."
Forwards: Stephen Archer, Rory Best, James Coughlan, Tom Court, Sean Cronin, Declan Fitzpatrick, Cian Healy, Jamie Heaslip, Chris Henry, Mike McCarthy, Jack McGrath, Kevin McLaughlin, Sean O'Brien, Paul O'Connell, Peter O'Mahony, Mike Ross, Mike Sherry, Devin Toner, Dan Tuohy
Backs: Isaac Boss, Tommy Bowe, Gordon D'Arcy, Keith Earls, Robbie Henshaw, Paddy Jackson, David Kearney, Rob Kearney ,Ian Madigan, Luke Marshall, Fergus McFadden, Conor Murray, Brian O'Driscoll, Eoin Reddan, Jonathan Sexton