#1 Mario Gotze
If you're wondering why Robert Lewandowski isn't on the list, it's because Dortmund didn't sell him. He left for free.
When Jurgen Klopp created his all-conquering Dortmund team, Goetze was at the heart of it. The young German was so impressive that many compared him to Lionel Messi
But in the summer of 2013, he broke the hearts of Dortmund fans by moving to their arch-rivals Bayern Munich for a then German record fee of €37 million. Things did not go well for the World Cup winner as he struggled with injuries at the Allianz Arena.
It was his move that crumbled Dortmund, as they never really managed to replace him or find a way to play their high pressing football without him.
Though he is now back from where he started, but he is a shadow of the player he once used to be.