Bayern Munich midfielder David Alaba suffered a knee ligament injury in their 2-0 victory over AS Roma in the Champions League on Wednesday, the club said.
The gifted 22-year-old Austria international was in outstanding form, setting up the first goal for Franck Ribery.
He was taken off injured in the 81st minute as Bayern cruised to the Champions League knockout stage after their win over the Italians secured them top spot in Group E.
“There is a problem with David. He was injured,” Bayern coach Pep Guardiola told reporters. “He will get checked out tomorrow when we will know more.”
The club later said on Twitter the player sustained “a medial collateral ligament injury”.
Bayern were already without a string of key injured midfielders including Bastian Schweinsteiger, Javi Martinez and Thiago Alcantara.
The Bavarians, who are also top in the Bundesliga, are undefeated in 16 games in all competitions this season.