Bayern and Germany goalkeeper Manuel Neuer injured again
Neuer injured his calf with no other players seemingly involved and limped off for Bayern replacement goalkeeper Sven Ulreich in the 53rd minute.
Bayern coach Niko Kovac says, "It's the same calf that was causing him problems two weeks ago. We have to wait on the MRI examination on Monday. It will be a blow for us if he injured himself."
Neuer has missed two games already in the second half of the season due to a thumb injury and left calf problem. The 33-year-old made only three league appearances for Bayern last season due to a hairline fracture in his left foot.
Still, Neuer retained his place for Germany as the defending champion exited the World Cup at the group stage last year.
Mats Hummels also limped off after the win in Duesseldorf. The Bayern defender appeared to have a hamstring injury.