Schalke have confirmed on their official website that holding midfielder Christoph Moritz will leave the club for Mainz at the end of the season.
The 23-year-old had an expiring contract with the Konigsblauen, and has now opted for a move elsewhere rather than ink a new deal with Schalke.
Moritz, who has been capped by Germany at Under-21 level, has signed a contract until the summer of 2017 with his new club.
The midfielder came through the ranks of the Alemannia Aachen youth academy, and joined Schalke in the summer of 2009.
He has since made 52 Bundesliga appearances for the Champions League hopefuls, but has failed to become a first team regular.
Moritz is currently recovering from torn knee ligaments.