Zanetti picked up an ankle injury in training on Monday and has been ruled out of the Azzurri's friendly with Northern Ireland on Tuesday evening.
The Internazionale ace has returned to Giuseppe Meazza to have the knock assessed by his club's medical staff.
He will undergo physiotherapy on the injury in the hope of being fit for the clash against Helsinki in Finland on June 11.
If Zanetti fails to recover in time, Azzurri coach Giovanni Trapattoni could call on the services of Milan's Massimo Ambrosini to bolster his engine room.
