The Austrian left-back was replaced by Rafinha in the 83rd minute at the VELTINS Arena after picking up an ankle injury. Bayern team doctor Volker Braun has been working intensively with the 23-year-old, but whether he will recover in time to face the Greek champions on Tuesday remains in doubt.
Franck Ribery will certainly miss the Olympiacos game, though he looks set to return in a few weeks. The France winger has been contending with an ankle injury of his own since March, but coach Pep Guardiola is optimistic after seeing Ribery complete a recent course of intensive rehabilitation.
"He’s taken a huge step forward in the last few weeks," said the former FC Barcelona boss. "Perhaps he will return in a week or two."