Hoffenheim snapped up the left-back on a free transfer last summer and he had a great first season at the club, making 32 league appearances for the side.
There is already talk of him leaving Hoffenheim after just one season and Dortmund have been working on a deal to sign him.
Newcastle and West Ham are interested in taking him to England, but there is also talk of Manchester United wanting him.
It has been claimed that Manchester United have not gone beyond making an initial enquiry for the left-back thus far.
The Premier League giants have their eyes on him but they have not made much progress on that front.
They have not made an offer for Raum, who is wanted by several sides this summer.
Tottenham and Manchester City are also believed to be keeping tabs on him, but Spurs are now unlikely to sign him after landing Ivan Perisic.
