AC Milan midfielder Ismael Bennacer (25) has been ruled out for at least six months after having surgery on his right knee, the Serie A club said on Tuesday.
Algeria international Bennacer was substituted in the 17th minute of his side's 2-0 Champions League semi-final first leg defeat by Inter Milan last week.
Milan said Bennacer had surgery in Lyon on Tuesday morning to repair the cartilage lesion in his right knee.
Bennacer has played 40 games in all competitions this season, registering three goals and two assists.
Milan take on Inter in the return leg of the semi-final at San Siro later on Tuesday. Manchester City host Real Madrid in the other semi on Wednesday with their tie level at 1-1.