The 22-year-old defender will enter the final year of his contract at Freiburg at the end of the season and he will not be signing a new deal with the club.
The centre-back is prepared to move on from the club in the summer and he has been linked with a move to England, where Newcastle are interested in him and Tottenham are keen.
But Dortmund are the ones who are pushing to sign him and it has been claimed that Schlotterbeck has already given his nod of approval to a move to the Westfalenstadion.
However, according to Sky Deutschland, the two clubs are far apart in terms of their respective valuations of the centre-back at the moment.
Freiburg want around €25m for the defender before agreeing to let him go in the next transfer window.
Dortmund believe that the German club are asking for too much money for a player who will only have a year left on his contract.
BVB are being conservative about what they want to spend on Schlotterbeck and are aiming to sign him for less than €20m.
The 22-year-old wants the move but will have to wait for the two clubs to reach a compromise over the next couple of months.
And it remains to be seen if Newcastle, who want at least one centre-back in the summer, swoop in to take advantage of the financial differences.
