Bastian Schweinsteiger and Franck Ribery have both been ruled out of Bayern Munich's Champions League quarterfinal at Porto on Wednesday.
Ribery, 32, has been sidelined ever since sustaining an ankle injury in the 7-0 win against Shakhtar Donetsk in the competition on March 11.
While returning to individual training, the French winger has not been able to fully recover in time for the match in Portugal.
Germany captain Schweinsteiger, meanwhile, is unavailable for selection because of "a stubborn viral infection," the club announced on Monday.
"It's a real shame but Bastian and Franck can't come with us," Bayern sporting executive Matthias Sammer told reporters in Munich.
There was better news for the Bundesliga leaders as centre-back Jerome Boateng, who was rested for Saturday's 3-0 victory over Eintracht Frankfurt, is set to return for the first leg on Wednesday.
Bayern are already without top scorer Arjen Robben, David Alaba and Javi Martinez, with the latter continuing to work on his comeback following an anterior cruciate ligament tear last August.
However, midfielder Thiago Alcantara and captain Philipp Lahm are slowly finding their rhythm following their respective injuries, and give Bayern coach Pep Guardiola further options for the Porto match.
Against Frankfurt at the weekend, Bayern's bench options consisted of just three outfield players and goalkeeper Manuel Neuer, who was rested in favour of Pepe Reina.
Guardiola could fill up the squad to play Porto with youngsters, with Sammer adding: "Pep will now decide whether to take along another of our young players."