Altintop out of Sporting second leg
"Hamit Altintop was injured in the 5-1 win against Hanover 96 and is not at the coach's disposal for the Sporting match," the club said on their website on Monday.
The Turkey international was expected to be out for two to three weeks, the club said.
Bayern are already without injured midfielders Franck Ribery and Tim Borowski as well as striker Luca Toni, who is still recovering from a heel injury, for their round of 16 return leg against Sporting.
The German champions won the first leg in Lisbon 5-0 and are all but guaranteed a place in the quarter-finals.
Altintop injured his ankle shortly after scoring Bayern's third goal on Saturday and limped off the pitch.