Milan have confirmed defender Fode Ballo-Toure is expected to miss four weeks after undergoing a shoulder operation.
The Senegal international, who was part of his country's World Cup squad, sustained an injury to his right shoulder during the Rossoneri's friendly against PSV on Friday.
Ballo-Toure joins Milan's lengthy injury list which also includes Zlatan Ibrahimovic, Mike Maignan, Rade Krunic, Divock Origi and Alessandro Florenzi.
A club statement read: "Milan announces that today the defender Fode Ballo-Toure has undergone the reduction and synthesis of a dislocation of the right shoulder at the IRCCS Galeazzi Sant'Ambrogio Hospital in Milan.
"The operation, which was performed by Dr. Pozzoni and his team, in the presence of the first team doctor Lucio Genesio, was perfectly successful. The time to return to full activity is estimated at four weeks."
Ballo-Toure has made seven appearances this season for the Rossoneri, who resume their Scudetto defence against Salernitana when Serie A restarts on Wednesday.