The 24-year-old reportedly passed a medical with Barcelona according to Mundo Deportivo last month.
The report went onto say that the examination was conducted by Dr. Hans-Wilhelm Müller-Wohlfahrt and the Spanish newspaper claims the medical was satisfactory.
Gündoğan took to Facebook to deny the rumours, his statement read: “In recent weeks, I, like you, read again and again that where I was signing was already agreed. Today I am in contract negotiations here, tomorrow I’m having a medical check there.
“At first I could still smile about it but when there was talk of ‘contract poker’ and ‘rip-off’ that painted me in a bad light.
“Yesterday an ominous number [regarding wage demands] appeared in the media and so I have now decided to say something about it.”
United are now the bookies favourites to sign the 24-year-old. Sky Bet slashed Gündoğan to sign for United’s odds from 5/2 to 1/2. Barcelona remain at 2/1 while Bayern Munich have risen from 13/8 to 4/1.
Dortmund CEO Hans Joachim Watzke has previously confirmed that Gündoğan will leave the club at the end of the season.
“Gündoğan will be leaving Borussia Dortmund this summer, that is a fact. I am very confident we will see various clubs coming in for him,” Watzke told SportBild.
Gündoğan has five assists and three goals in 33 appearances for Dortmund despite spending much of the season out injured and is almost certain to leave the Bundesliga giants over the summer.