The Turkey international has failed to settle at Real Madrid but the German champions are not actively seeking to re-sign the 23-year-old midfielder
The Turkey international only left for Real Madrid last summer, but has struggled to nail down a regular berth in Jose Mourinho's starting line-up and has been repeatedly linked with a move away from the Bernabeu this summer.
Dortmund have been mooted as a possible destination and while Watzke is reluctant to rule out re-signing the midfielder, he revealed that it is not exactly on the cards.
"Sahin coming back to us is not planned, either by him or us," Watzke told Sport Bild.
"However, he' s a boy with a Dortmund past and he came from our youth team, so I would never rule out a return."
Madrid paid a reported €10 million for Sahin, who still has four years to run on his contract with the Liga champions.