Franck Ribery faces a race against time to be be fit for Bayern Munich's Champions League last-16 clash with Arsenal after being ruled out for two weeks with a hamstring injury.
Bayern take on Arsenal in the first leg at the Allianz Arena on February 15, after facing Schalke, Wolfsburg and Ingolstadt in the Bundesliga.
But they may have to do so without the 33-year-old winger after he had to pull out of training on Tuesday.
A Bayern statement read: "Franck Ribery had to stop training early on Tuesday morning because of a strain in the right hamstring.
"He will probably not be available for two weeks due to the injury."
There was better news for Arturo Vidal (rib), who returned to training with the rest of the squad, and Arjen Robben, who had trained alone on Monday.
Kingsley Coman, Xabi Alonso and Philipp Lahm all trained individually ahead of Saturday's clash with Schalke.
Ribery has made 13 appearances for leaders Bayern in the Bundesliga this season, scoring two goals.