Inter right-back Maicon will fly to Brazil to have surgery on a knee problem, the Italian club have announced.
The Brazil international sustained the injury in a training session last week and was allowed to rest in the last two days as a precaution.
Test scans have shown that Maicon has suffered an injury to the medial meniscus of his right knee, which will require immediate surgery.
The operation will take place in Brazil and will be conducted by Jose Luis Runco, doctor of the Brazil national team and a friend of Franco Combi, Inter's chief of medical staff.
The news of Maicon's absence will come as a huge blow to Inter coach Gian Piero Gasperini, with no estimation of the player's recovery time provided yet.
The 2010 Champions League winners, who lost to AC Milan in the Supercoppa Italiana, have their Serie A opener scheduled for 28 August at Lecce.