Viktor Fischer has left Championship side Middlesbrough to join Mainz, the German side have announced.
The 23-year-old has signed a contract until 2021 with the Bundesliga club, leaving Teesside after just 12 months.
The Denmark international joined Boro from Ajax, but made only 13 Premier League appearances, and failed to score, as the club were relegated from the top flight.
Speaking to the Bundesliga club's official website, he said: 'Mainz is the right club for me to enjoy my football again.