Werder Bremen are already facing up to the prospect of losing Serge Gnabry.
The Germany U23 winger couldn't get a game at West Brom and was sold by Arsenal in August.
However, such has been his form, Werder are already fearing they could lose him to a bigger club by the end of this season.
Darmstadt coach and former Werder star Norbert Meier told BILD: "When I watch Gnabry, I do not know how long he'll play in Germany.
"He is so difficult to play against. When he gets the ball, he immediately attacks the opponent."
New Werder coach Alexander Nouri said: "Serge is a fantastic player. One who can make the difference.
"We are glad that he is with us."