Bayern Munich forward Thomas Muller is facing a race against time to be fit for their Champions League last-16 second leg with Arsenal next month.
The German international scored the second goal as Pep Guardiola's side established a 2-0 advantage heading into the reverse fixture at the Allianz Arena on March 11.
He found the net twice more in the 4-0 Bundesliga victory over Hannover on Sunday, but was substituted after an hour with what scans later proved to be a hamstring strain in his right thigh.
A statement from Bayern's club doctor Hans-Wilhelm Muller-Wohlfahrt on their official website announced that Muller would take a "mandatory five-day break" and ruled him out of this weekend's game with Schalke.
With Franck Ribery and Xherdan Shaqiri already fitness doubts, Bayern will be hoping that Muller recovers in time to face the Gunners as they look to move a step closer to defending their European crown.
