The Bundesliga champions have been interested in the player, but do not want to pay more than €6 million for the striker, whereas their rivals are holding out for €9m.
By rejecting an extension to his contract, that would have taken him up to 2016, Schieber is effectively forcing through the transfer.
And Stuttgart manager Fredi Bobic has expressed his disbelief at the player's decision.
"For us, this comes as a surprise," he told Bild.
The German striker has scored three times in 31 matches for Stuttgart.