The Italian right-back will miss Sunday's encounter with Fiorentina after picking up an injury against Malaga, which will keep him out until the end of the month
The full-back was substituted after just six minutes of the Rossoneri's 1-1 draw with Malaga in the Champions League, and the club confirmed on their website that he suffered a lesion to his right quadricep.
More tests will be carried out on the injury, but the prognosis is that he will be missing for at least 15 days, though he was able to train in the gym as his team prepared for Sunday's match with Fiorentina.
The Italy international had felt a twinge during the warm-up on Tuesday night, but coach Massimiliano Allegri chose to risk the 25-year-old from the start, only to replace him with Mattia De Sciglio in the opening minutes.
The San Siro club are currently 10th in Serie A after a slight upturn in their fortunes, though the injury to their first choice right-back will be a blow ahead of some crucial matches.