Further tests on the problem carried out on Monday have revealed that Balotelli's injury is worse than first feared, and Italy coach Cesare Prandelli admitted that he had little choice but to send Balotelli home.
He is quoted by Football Italia as saying: "Balotelli was very disappointed, but there was no time for him to recover.
"In any case, there was no pressure from Milan on me or the Federation to bring him straight back to Italy.
"Without Mario we will have to try to work more on the collective."
The 22-year-old will return to AC Milan for further examination of the injury this week, forcing Prandelli to shuffle his squad ahead of Thursday's repeat of the European Championship final against La Roja.