Riccardo Montolivo has gone under the knife to remove a bone fragment from his ankle and will be out for six weeks.
The Fiorentina captain has been struggling since the World Cup in June and playing regularly with the aid of pain-killing injections.
When it became clear the problem would not be cured without surgery, he was booked in for an operation.
Montolivo went under the knife in Amsterdam today, confirmed the official club website, at the hands of Professor Van Dijk.
He is expected back on the playing field in around five to six weeks.