That rumour about a Sahin/Gündogan swap is an old one, which emerged in March (unless there are new 'details'). Given that BVB started renewal talks with Gündogan in the summer, after those rumours, I don't see much truth to it. Whether Gündogan will leave is a different question. He has said he feels good at Dortmund and would like to renew, so I expect him to. As matters stand, the talks have been put on hold, allegedly because of his injury, since he'd prefer to come back to playing first. If in the end he won't renew, I can see BVB selling him next summer to avoid letting him go for free in 2015. Not sure he'd be interested in RM though.