David Alaba is set to miss the start of Bayern Munich's Champions League campaign after tearing a muscle in his left thigh.
The 27-year-old suffered the injury in the warm-up before Bayern's 1-1 draw at RB Leipzig on Saturday.
Jerome Boateng replaced him in the starting XI, with Lucas Hernandez moving to the left side of defence.
Bayern did not confirm a timeline for Alaba's return but head coach Niko Kovac will have to weigh up his options for Wednesday's home clash against Red Star Belgrade.
"Bayern will be without David Alaba for a spell after the Austria international tore a muscle in his left thigh while warming up for Saturday's top Bundesliga match away to RB Leipzig," the club confirmed in a statement.
Linked to Barcelona during the close season, Alaba started each of Bayern's opening three Bundesliga fixtures and scored in the 6-1 thrashing of Mainz last month.
The German champions remain two points behind leaders Leipzig, while Borussia Dortmund sit second.