كتب : Omar AbdelAziz
"We at FSV Mainz 05 have a clear idea of how a manager should go along with a squad and its environment," Mainz general manager Christian Heidel said.
"Team-work, a close relationship with the squad and internal communications are key in this.
"We feel Mainz 05 and Jorn Andersen do not have these roots in common any longer as the manager has headed into another direction."
Reports suggested that Mainz players, which include Egyptian striker Gamal Hamza, complained of Andersen's tough training approach.
However, the embarrassing German Cup exit at the hand of fourth-division VFB Lubeck at the weekend was the straw that broke the camel's back.
Andersen guided Mainz to promotion last season and was about to be the first Norwegian to manage a Bundesliga side.
Mainz are yet to name a successor to the 46-year-old, but youth team manager Thomas Tuchel is reportedly tipped for the job.