The Rossoneri have signed Adil Rami from Valencia in an attempt to patch up the leaky defence, but they are still looking for defensive reinforcements.
According to Tuttosport, Milan could make a move on long-term target Davide Astori in the January transfer window.
The 26-year-old has been putting in some impressive displays for Cagliari and he has even played himself into the plans of Italy boss Cesare Prandelli.
Meanwhile, the Rossoneri are also monitoring the progress of Isolani full-back Nicola Murru, who has exploded onto the biggest stage this season.
The 18-year-old has started 9 Serie A games this term and he is seen as a hot prospect for the future.
AC Milan are currently on a four-match winless run in Italian Serie A, and they are priced at 4/9 to return to winning ways at home against Genoa.