Inter Milan defender Danilo D'Ambrosio suffered a knee ligament injury in Wednesday's 2-1 Serie A loss at Sampdoria, the club said on Thursday.
Italy's Sky Sport said the 32-year-old full back could be out of action for four to five weeks.
D'Ambrosio left the field shortly before the end of the game after a collision with Sampdoria midfielder Mehdi Leris, having come on to replace Milan Skriniar in the 81st minute.
"The tests revealed that the Italian has strained the medial collateral ligament of his left knee. His condition will be reassessed next week," Inter said in a statement.
The Italy international will miss Sunday's Serie A match at AS Roma and Wednesday's Coppa Italia game away to Fiorentina.
Inter are second in the standings on 36 points from 16 games, a point behind AC Milan and three points ahead of Roma.