AC Milan have confirmed midfielder Lucas Biglia will miss the next four months after suffering a calf injury during training last week.
Scans confirmed surgery was required to fix the issue, and Biglia was operated on in Finland on Thursday.
"The injury suffered by Lucas Biglia last Wednesday during the morning training session involved the lesion of the myotendinous junction of the medial segment of the right calf," a Milan statement read.
"The operation, carried out today in Finland by professor Sakari Orava in the presence of the team doctor Stefano Mazzoni, was successful.
"Full healing will take four months."
Biglia had featured in all nine of Milan's Serie A games and two Europa League clashes before suffering the injury.