AC Milan defender Pierre Kalulu has had surgery and is expected to be out of action for around four months.

The 23-year-old centre-half ruptured a thigh muscle in last weekend’s 2-2 draw at Serie A rivals Napoli and had an operation to repair the damage on Thursday.

Milan said on their official website: “AC Milan can confirm that Pierre Kalulu underwent surgery today to repair a complete rupture of his left rectus femoris tendon.