Borussia Dortmund's sporting director Michael Zorc has revealed that Nuri Sahin's determination to re-join the club made the move happen.
Sahin moved back to Dortmund on loan from Real Madrid on Friday, ending his short spell with Liverpool.
Zorc has praised Sahin's qualities, insisting that he will be a "great asset" for Dortmund in the Bundesliga and Champions League.
"I think it's quite clear how happy everyone involved is about the deal. And, quite frankly, this transfer wouldn't have been possible had Nuri not been so determined," said Zorc.
"Nuri accepted what we offered as for him it was all about wearing Borussia Dortmund's shirt again. There wouldn't have been a chance to sign him otherwise. This of course shows that his dedication to BVB isn't just empty words. He has a hugely strong desire to play for us, and for us only.
"I'm sure he'll be able to link up very well with all our midfielders and his footballing ability is outstanding. But it's not just that, Nuri's also such a positive character, and he will give it 100% with BVB."
Sahin orginally left Dortmund for Madrid in 2011.