Kevin-Prince Boateng may not have been called up by Ghana for the African Cup of Nations but AC Milan will lose him for a month anyway.
The German-born 24-year-old has pulled his hamstring and is expected to be out for a month, the club said.
Goalkeeper Christian Abbiati is also suffering from a calf problem which is expected to be keep him out of the side for a week when further tests will be conducted.
Milan have moved quickly to replace Boateng, however, by re-signing German teenager Alexander Merkel from Genoa.
The 19-year-old moved to Genoa from Milan in the summer as part of the deal which brought Boateng to the Serie A champions.
Kazakh-born Merkel is part-owned by both clubs but Genoa hold his licence so Milan have had to sign him on loan.