Bonaventura out for up to nine months after surgery

AC Milan's Giacomo Bonaventura has had successful surgery in the United States, but is not expected to play again this season.

AC Milan midfielder Giacomo Bonaventura

Giacomo Bonaventura will be sidelined for up to nine months following an operation on his knee, AC Milan have confirmed.

The midfielder had surgery on an osteochondral lesion to his left knee in the United States on Tuesday.

Milan released a statement to confirm the procedure in Pittsburgh had been a success, but they do not expect him to play again this season.

Bonaventura had enjoyed a strong start to the season, scoring three times in eight Serie A appearances, but has not played since the 2-1 Europa League defeat to Real Betis at San Siro on October 25.

It was initially speculated the Italy international would only be out for up to five months.

The news is a blow to head coach Gennaro Gattuso, with Lucas Biglia battling a calf problem this season and Hakan Calhanoglu also struggling for full fitness.