The Egyptian striker was nursing a knee injury in his homeland to resolve problems related to his mandatory military service.

"Mohamed Zidan has completed all formalities with the Egyptian military and is expected to return to Dortmund this weekend," Dortmund said on their official website.

"Zidan had to extend his stay in his homeland because as an under 30 year old man he was theoretically still eligible for military service.

"The BVB player has been in Egypt to continue his rehab, for a few weeks also under the guidance of BVB physio Thorben Weste and fitness coach Florian Wangler."

Zidan suffered a cruciate knee ligament damage in April in a Bundesliga game between Dortmund and Hoffenheim.

He missed the team's first two league games and was also absent when they reached the Europa League group stage at the expense of Azerbaijani side Qarabagh.

"After his return to Dortmund, Zidan will be examined by BVB team doctor Markus Braun who will then decide, together with the coaching team, about the next steps in the rehabilitation process," the club added.

"Zidan will now begin the third phase of his recovery in Dortmund and has set October/November as his comeback target."

The 28-year-old, who forms a productive partnership with Paraguayan striker Lucas Barrios upfront, scored six league goals and dished out many assists last season.