Schalke coach Ralf Rangnick has stepped down because of health reasons, the Bundesliga club have announced.
Rangnick, who succeeded Felix Magath at the German side in March, said he was suffering from exhaustion.
It was not immediately clear how long the coach would be out or whether he would be returning to Schalke.
A club official said on Thursday: "He has stepped down after discussions this morning."
The 53-year-old led Schalke to the UEFA Champions League semi-finals and German Cup success last season.
The coach said in a statement on the club's official website that he had stepped down because of "exhaustion syndrome".
"After a long and mature consideration I decided that I needed a break," said Rangnick.
"This decision is very hard but my current energy level is not sufficient to be successful and especially to further develop the team."
Rangnick, who joined Schalke after leaving Hoffenheim in January, will be replaced on an interim basis by coach Seppo Eichkorn.
"His decision deserves respect," said Schalke sports director Horst Heldt.
"We also believe that health should be put above any professional targets and challenges."
Schalke currently sit ninth in the Bundesliga after three wins and three defeats from their opening six games.