American-born Rossi scored 16 league goals last season despite only starting two games in 2014 due to a long-term knee injury layoff.
Cassano shone as Parma finished sixth in Serie A and he will go to Brazil along with flamboyant Torino forwards Alessio Cerci and Ciro Immobile, who scored 35 league goals between them in Giampiero Ventura's exciting side.
Immobile is set to sign for Borussia Dortmund in the close season.
Italy lost midfielder Riccardo Montolivo to a broken leg following an accidental collision with Ireland defender Alex Pearce on Saturday. Alberto Aquilani takes his place in the squad.
Paris St Germain midfielder Marco Verratti played his way into the squad following a good display against the Irish and Napoli's Lorenzo creative attacker Lorenzo Insigne was preferred to AS Roma youngster Mattia Destro.
There were few surprises in goal or at the back with captain and keeper Gianliugi Buffon set to extend his record of 139 Italy appearances.
Inter Milan's Andrea Rannochia will remain in reserve given the injury niggles affecting a number of defenders.
Defenders: Ignazio Abate (AC Milan), Andrea Barzagli (Juventus), Leonardo Bonucci (Juventus), Giorgio Chiellini (Juventus), Matteo Darmian (Torino), Mattia De Sciglio (AC Milan), Gabriel Paletta (Parma)
Midfielders: Alberto Aquilani (Fiorentina), Antonio Candreva (Lazio), Daniele De Rossi (AS Roma), Claudio Marchisio (Juventus), Thiago Motta (Paris St Germain), Marco Parolo (Parma), Andrea Pirlo (Juventus), Marco Verratti (Paris St Germain)
- Sports & Recreation
- Cesare Prandelli
- Ciro Immobile
- Alessio Cerci
- Lorenzo Insigne
- Alberto Aquilani
- Marco Verratti
- Daniele De Rossi