Mainz sporting director Christian Heidel has confirmed Brajan Gruda's move to Brighton includes major bonuses.
The deal is said to be worth a fee rising to over €30m and Heidel says Mainz will benefit as the winger continues to develop in England.
Advertisement
Advertisement
"Brajan has the ability to become an outstanding player," Heidel told BILD. If this potential is exploited, we want to participate in it.
"And that is how the contract is designed."
Gruda is yet to appear for Brighton this season due to injury.