Milan centre-back Mattia Caldara has undergone surgery on the knee injury he picked up in training in midweek, with the 25-year-old expected to spend up to six months on the sidelines as a result.
The Italian international joined the Rossoneri from Juventus for €35m last summer, but is yet to make a league appearance following a string of fitness issues. His early San Siro career was hampered by minor problems before a ruptured achilles tendon kept him out for four months, the defender only returning to the side last week.
Caldara - who was unveiled as a Milan player alongside Gonzalo Higuain in August - made his comeback during the Coppa Italia semi final defeat to Lazio last week, putting in a strong performance despite the loss.