Borussia Dortmund could be without top scorer Pierre-Emerick Aubameyang when they take on Bayern Munich in the DFB-Pokal on Wednesday.
Aubameyang scored his 21st goal of the season as Dortmund defeated Hoffenheim in the Bundesliga on Saturday, but sustained a muscular injury during a training session on Monday.
Head coach Peter Stoger is unsure whether the Gabon striker will be fit in time for the Klassiker at the Allianz Arena, though he is confident the defending champions have enough options to cope with his potential absence.
"The availability of Aubameyang for Wednesday is still not certain. We have to wait," Stoger told a pre-match news conference.
"We have several options in the event of Aubameyang missing out."
Aubameyang has scored six goals in as many appearances and has this week reportedly agreed to extend his stay at Signal Induna Park through to 2021.
