Milan announced Ignazio Abate is likely to miss Sunday's trip to Juventus with a thigh problem.
The full-back had come out of Wednesday's 2-0 win over Viktoria Plzen with a knock and recovery time has been slower than expected.
“AC Milan announce that Ignazio Abate is suffering from a thigh problem that has prevented him from taking part in yesterday's and today's training sessions,” read a statement on the club website.
“Over the next few days his condition will be re-evaluated through further medical tests.”
This suggests it is highly unlikely Abate will be able to recover in time for the Sunday night Serie A clash with Juventus.
Also expected to miss out are Robinho, Alexandre Pato, Gennaro Gattuso, Massimo Ambrosini, Philippe Mexes, Mathieu Flamini and Kingsley Boateng.