Fortuna Düsseldorf have confirmed the arrival of Julian Koch from 1. FSV Mainz 05 on a three-year deal.
Koch, formerly of Borussia Dortmund, joins the Westfalen side after a year on loan at fellow 2. Bundesliga team, FC St. Pauli.
The 24-year-old had joined Mainz in summer 2013, though game time was limited.
Both clubs agreed that the fee will not be disclosed for the eight-time youth international.
New head coach, Frank Kramer, was pleased to have committed such a 'mentally strong' player:
"As a defensive midfielder, he convinced us with both his aggressiveness in winning the ball, as well as his abilities to read the game.
"He will help us through its high quality on the pitch and his strong personality quickly."
Koch admitted: "Fortuna is a great club with ambition and Dusseldorf is a great city.
"I had really good conversations with Frank Kramer, who convinced me about the transfer.
"Furthermore, I am sure that I can continue to develop best under him and at the Fortuna."
Quotes via f95.de