Riccardo Montolivo is unlikely to play again before Christmas after undergoing surgery on a fractured tibia on Monday.
The AC Milan midfielder required an operation after his World Cup hopes were ended by an injury he picked up during Italy's penultimate warm-up match before flying out to Brazil against Republic of Ireland on Saturday.
The surgery, performed by Dr Herber Schoenhuber, Roberto Pozzoni and professor Riccardo Accetta and assisted by Milan's medical team, was "technically successful," according to a statement on the Rossoneri's website.
However, it will take at least six months before Montolivo can return to action, meaning he will miss most of the first half of next season.
"This is how long it takes biologically to heal," Dr Schoenhuber said. "I can rule out four or five months being sufficient. A nail has been inserted into the bone to heal the fracture.
Montolivo, 29, will be examined again in 40 days to see how his left leg is responding to the surgery. A more accurate estimate on the recovery time will then be made.
The 2014-15 Serie A season starts on Aug. 30 while Montolivo will also miss Italy's Euro 2016 qualifiers in September, October and November.