The Everton midfielder made 43 appearances for club and country this season and will be afforded a rest for the fixtures against Turkey, Italy, Costa Rica and Portugal.
Joey O'Brien and Darren Randolph have also been cut from coach Martin O'Neill's initial 32-man selection.
Reports had suggested Stoke City midfielder Stephen Ireland could come in to the fold and end his seven-year international exile, though he remains unselected.
O'Neill revealed when the full squad was announced earlier this month that he had contacted the playmaker over a return to the international arena.
Elsewhere, Rob Elliot will hope to make up for missing his pre-wedding celebrations by earning his international debut, with centre-back Shane Duffy also holding out hope of making his senior bow.
Hull City trio Shane Long, David Meyler and Stephen Quinn have also been selected.
Ireland take on Turkey at the Aviva Stadium on May 25, before facing FIFA World Cup hopefuls Italy at Fulham's Craven Cottage home.
O'Neill's side will also test their mettle against World Cup sides in the shape of Costa Rica and Portugal, with both of those games to be played in the United States.
Squad in full:
Goalkeepers: Rob Elliot (Newcastle United), David Forde (Millwall)
Defenders: Ciaran Clark (Aston Villa), Seamus Coleman (Everton), Damien Delaney (Crystal Palace), Shane Duffy (Everton), Stephen Kelly (Reading), Richard Keogh (Derby County), John O'Shea (Sunderland), Alex Pearce (Reading), Stephen Ward (Brighton and Hove Albion), Marc Wilson (Stoke City)
Midfielders: Paul Green (Leeds United), Jeff Hendrick (Derby County), Wes Hoolahan (Norwich City), James McClean (Wigan Athletic), Aiden McGeady (Everton), David Meyler (Hull City), Anthony Pilkington (Norwich City), Stephen Quinn (Hull City), Glenn Whelan (Stoke City)
Forwards: Simon Cox (Nottingham Forest), Kevin Doyle (QPR), Robbie Keane (LA Galaxy), Shane Long (Hull City), Daryl Murphy (Ipswich Town), Connor Sammon (Derby County), Anthony Stokes (Celtic), Jon Walters (Stoke City)
