The Azzurri will host San Marino in a friendly in Bologna on May 31 then visit the Czechs in Prague on June 7 for a World Cup qualifier.
In Group B of European qualifying, Italy holds a three-point lead over Bulgaria. The Czechs are next, five points behind Italy.
Tiny San Marino is last in Group H, with no goals scored and 29 conceded.
Balotelli and El Shaarawy have scored a combined 27 goals in Serie A this season, while Cassano has struggled at Inter and broke his hand in training Wednesday.
Several players were left out for Italy's under-21 squad, which will play the European Championship in Israel next month, including Paris Saint-Germain midfielder Marco Verratti, Napoli forward Lorenzo Insigne and Roma forwards Mattia Destro and Alessandro Florenzi.
Coach Cesare Prandelli must trim the squad to 23 players for the Confederations Cup by June 3.
Defenders: Ignazio Abate (AC Milan), Luca Antonelli (Genoa), Davide Astori (Cagliari), Andrea Barzagli (Juventus), Leonardo Bonucci (Juventus), Giorgio Chiellini (Juventus), Mattia De Sciglio (AC Milan), Christian Maggio (Napoli), Angelo Ogbonna (Torino), Andrea Ranocchia (Inter Milan).
Midfielders: Alberto Aquilani (Fiorentina), Giacomo Bonaventura (Atalanta), Antonio Candreva (Lazio), Alessio Cerci (Torino), Daniele De Rossi (Roma), Emanuele Giaccherini (Juventus), Claudio Marchisio (Juventus), Riccardo Montolivo (AC Milan), Andrea Pirlo (Juventus), Andrea Poli (Sampdoria).
Forwards: Mario Balotelli (AC Milan), Stephan El Shaarawy (AC Milan), Alessandro Diamanti (Bologna), Alberto Gilardino (Bologna), Sebastian Giovinco (Juventus), Pablo Osvaldo (Roma), Marco Sau (Cagliari).