The German midfielder is on the receiving end of offers from both United and Real Madrid, and has admitted he will carefully consider his options, with his Dortmund contract set to expire in 2015.
Gundogan has missed a long spell of the season through injury, and has used that time to decide on his future.
“I have not made a final decision yet. BVB are the first team I am talking to,” the midfielder said.
“I will soon make a well-thought decision. But I am keeping my options open at this point. Borussia Dortmund have not set me an ultimatum. I am just trying to get healthy again and get back to my best form. That’s the main priority for BVB and for myself.”
United fans have called for David Moyes to sign a midfielder, with supporters unhappy with the contributions from Tom Cleverley, and summer signing Marouane Fellaini. And after a tough season so far, Moyes has been urged to spend big this month, with Gundogan reportedly one of the club’s top targets.
It would be a big blow for Dortmund to lose the 23-year-old, after selling Mario Gotze last summer, and Robert Lewandowski on a free transfer in this summer.