The striker saw a specialist in Munich yesterday and the decision to operate immediately was taken by all involved.
The German international had suffered a relapse of an inflammation around the metatarsal bones in his right foot.
The centre-forward will return to action once the international break is over in the hope that he could feature against Atalanta on October 20.
Meanwhile, Etrit Berisha suffered a thigh strain on Wednesday which will be assessed again at the start of next week.
- Sports & Recreation