AC Milan captain and Italy midfielder Riccardo Montolivo issued a heartfelt thanks to fans for their support following his serious knee injury, while he even responded to death wishes.

Montolivo is facing six months on the sidelines after undergoing surgery to repair a torn anterior cruciate ligament in his left knee suffered during Italy's 1-1 World Cup qualifying draw with Spain on Thursday.

The 31-year-old's injury has highlighted the best and worst of supporters, with some fans even wishing death upon the 64-time international.

And Montolivo used Facebook to issue a dignified reply to the vile comments.

"A heartfelt thanks to everyone who spared a thought for me ... fans, colleagues, professionals," he wrote.

"It was lovely, at such a stressful time, to receive so many expressions of care and affection.

"And love to all those who wished me a broken tibia and fibula, the rupture of all my ligaments and death...with the hope that life is able to make you grow in terms of manners and respect for other human beings."

Montolivo had played in all seven of Milan's Serie A matches this season prior to earning a call-up to Giampiero Ventura's Italy squad.