Eugen Polanski has signed a permanent deal with Mainz after a successful loan spell from Getafe.
The 24-year-old was loaned from the Spanish club until next June, but he has now agreed on a new three-year contract with the Bundesliga side and will not be returning to Spain next summer.
The midfielder was delighted to earn a full-time stay at Mainz.
"Mainz is an excellent club for me," said Polanski. "Next year, we will move to a fantastic brand new stadium and I feel very happy in the region with my family.
"I am really glad to have completed this transfer so soon as this gives me room to plan beyond next summer."