That is the view of German outlet Bild, with journalist Christian Falk claiming Jadon Sancho may be heading back to Germany.
The winger is out of favor at United under boss Erik ten Hag, with Sancho training alone lately.
The source claims that Dortmund are keen to bring him back, but the deal does have some roadblocks.
United would want to sign Dortmund star Donyell Malen to give them more options up front.
United do value Sancho higher than Dortmund value Malen, but a compromise may be possible.