Rossi scored for the Azzurri in their 3-0 friendly win over Northern Ireland before leaving for South Africa.
Santon started 14 games for Inter's Serie A championship squad.
"We will be up against quality opponents who are not here by fluke," said Italy coach Marcello Lippi after his team held its first training session in Pretoria.
Italy will play games against New Zealand on Wednesday and a Tshwane all-star team on Friday.
Goalkeepers: Gianluigi Buffon (Juventus), Marco Amelia (Palermo), Morgan De Sanctis (Galatasaray, Turkey).
Defenders: Fabio Cannavaro (Juventus), Giorgio Chiellini (Juventus), Gianluca Zambrotta (AC Milan), Andrea Dossena (Liverpool, England), Alessandro Gamberini (Fiorentina), Fabio Grosso (Lyon, France), Nicola Legrottaglie (Juventus), Davide Santon (Inter Milan).
Midfielders: Mauro Camoranesi (Juventus), Daniele De Rossi (Roma), Simone Pepe (Udinese), Andrea Pirlo (AC Milan), Gennaro Gattuso (AC Milan), Riccardo Montolivo (Fiorentina), Angelo Palombo (Sampdoria).
Forwards: Alberto Gilardino (Fiorentina), Vincenzo Iaquinta (Juventus), Fabio Quagliarella (Udinese), Luca Toni (Bayern Monaco, Germany), Giuseppe Rossi (Villarreal, Spain).