Long has only played twice in the Premier League this season due to injury woe, but is selected by Martin O'Neill for the first time.
Those games will prepare them for a home World Cup qualifier with Austria on June 11.
Seamus Coleman, Ciaran Clark and David Meyler are among the regular players not available due to injury, but Marc Wilson is back.
Goalkeepers: Colin Doyle (Bradford City), Rob Elliot (Newcastle United), Keiren Westwood (Sheffield Wednesday), Darren Randolph (West Ham).
Defenders: Cyrus Christie, Richard Keogh, Alex Pearce (Derby County), Paul McShane (Reading), Shane Duffy (Brighton & Hove Albion), John O'Shea (Sunderland), Andy Boyle (Preston North End), John Egan (Brentford), Marc Wilson (West Brom), Kevin Long, Stephen Ward (Burnley), Matt Doherty (Wolves).
Midfielders: Aiden McGeady, James McCarthy (Everton), Glenn Whelan (Stoke City), Jeff Hendrick, Robbie Brady (Burnley), Harry Arter (Bournemouth), Conor Hourihane (Aston Villa), Stephen Gleeson (Birmingham City), Eunan O'Kane (Leeds United), Darron Gibson (Sunderland), Liam Kelly (Reading), Wes Hoolahan (Norwich City), James McClean (West Brom), Callum O'Dowda (Bristol City), Daryl Horgan (Preston North End), Jonathan Hayes (Aberdeen).
Forwards: Kevin Doyle (Colorado Rapids), David McGoldrick (Ipswich Town), Daryl Murphy (Newcastle United), Shane Long (Southampton), Jonathan Walters (Stoke City), Adam Rooney (Aberdeen).