Javi Martinez has been ruled out "for the foreseeable future" after sustaining a thigh injury during Bayern Munich's draw with RB Leipzig on Saturday.
The Spanish midfielder lasted just 25 minutes at the Allianz Arena and was replaced by Jamal Musiala, who scored Bayern's first goal in a thrilling game that ended 3-3.
Martinez will be unavailable for the Champions League meeting with Lokomotiv Moscow on Wednesday, though the reigning champions are already guaranteed to finish top of Group A.
A Bayern statement read: "Bayern will be without Javi Martinez for the foreseeable future. The Spain international suffered a muscle injury to his left thigh in the Bundesliga top-of-the-table clash against RB Leipzig on Saturday. The diagnosis was confirmed after an examination by the German record champions' medical unit."
The 32-year-old's future with Bayern is uncertain as his contract is due to expire at the end of the campaign.
Martinez has only made 24 Bundesliga appearances since the start of last season – nine of which have come as part of the starting line-up.
During that time, Bayern have averaged fewer goals scored (2.7 to 3.5) and more conceded (1.3 to 0.9) when Martinez has featured. They also attempt fewer shots (16.5 to 18.8) and allow the opposition more (10.4 to 8.5) when he is involved.
However, their win percentage remains the same at 75 per cent whether the Spaniard plays or not.