Bayern Munich have announced that club captain Philipp Lahm suffered a "serious injury" in training.
The German champions said on their Twitter page this afternoon that they will find out how serious the injury is later today.
"Philipp Lahm suffered a serious injury in training," the club said. "He is currently undergoing an examination. Diagnosis due by this evening."
Lahm, 31, has started every Bundesliga game for Bayern this season, scoring twice.