Gundogan’s fitness has been a cause for concern after the 25-year-old missed a year of football due to a back injury.
The German outlet Bild have claimed Gundogan was seen with his calf bandaged following Dortmund’s win over Berlin.
The report goes onto state that Gundogan ‘walked silently and frustrated’ in the dressing room.
The injury comes off the back of another injury Gundogan picked up in March which kept him out for a month.
Manchester City are close to finalising the transfer of Gundogan according to the Daily Mail. The Sun newspaper claims that City director of football Txiki Begiristain and Pep Guardiola have managed to convince the Germany international of Turkish origin to join the club after weeks of talks.