Mainz are understood to have signed rising star Marcel Risse from Bayer Leverkusen on a one-year loan deal.
Risse is all set to join the Werkself's league rivals and is expected to undergo a medical on Wednesday, according to Kicker-Sportmagazin.
Mainz are expected to have an option to buy the player on a three-year deal at the end of the season for an undisclosed transfer fee, which has already been negotiated.
The 20-year-old winger is one of Germany's brightest prospects having come through Leverkusen's youth academy and made his debut for the club back in May 2008.
However, the highly-rated starlet failed to secure regular first-team action under former head coach Bruno Labbadia and new trainer Jupp Heynckes has decided to farm out the youngster with a view to a permanent move.
Mainz boss Christian Heidel is understood to be delighted to have captured the extremely talented Risse.
The winger was loaned to Nurnberg in January 2009 for 18 months where he made 32 league appearances and has also appeared for Germany Under-21s.