Roma defender David Astori has sprained his right knee and will likely be out of action for about three weeks.

Astori injured his knee in Wednesday's 5-1 victory over CSKA Moscow in the Champions League.

Roma says the Italy defender, who has also injured his medial collateral ligament, has already started treatment.

No timeframe is specified for Astori's return but he is likely to be out for two or three weeks, missing the Serie A matches against Cagliari, Parma and Hellas Verona, and the Champions League match at Manchester City.

The 27-year-old Astori could return for the visit to Juventus on Oct. 5.