Cologne have terminated the contract of sporting director Jörg Schmadtke by mutual consent, the club confirmed on Monday.
The decision came after intensive talks in which the two parties expressed a difference of opinion regarding the "sporting direction" of the club.
"Jörg Schmadtke has done a very good job for Cologne," commented club president Werner Spinner. "He led us back into the Bundesliga and played a big role in our return to European competition after a 25-year absence. We're very grateful to him for that and he deserves credit. We wish him and his family all the best for the future."
Schmadtke, who had a contract until 2023, thanked the club for their "full backing and cooperation" during a memorable four-year tenure.
After gaining promotion as Bundesliga 2 champions in 2015, Cologne have enjoyed 12th-, ninth- and fifth-placed finishes in the Bundesliga. The Billy Goats are winless after nine league matches so far this season, however, and currently sit bottom of the standings.