Werder Bremen are yet to find out whether they can play new signing Sambou Yatabare against Borussia Monchengladbach on Friday.
Yatabare, 26, who joined Bremen from Standard Liege last week, was banned by the Royal Belgian Football Association after stepping on an opponent in his last match for his old club.
According to regulations, a player has to sit out a ban regardless of the league he is playing in.
However, Bremen are arguing that when signing Yatabare, he was not yet banned and so should be eligible to play his first Bundesliga match at Monchengladbach.
The German Football Association (DFB) has yet to confirm that the midfielder can play on Friday, with kicker saying that Bremen have only received vague information so far.
"That's deplorable for both the player and the club," Bremen CEO Thomas Eichin told kicker. "We've acted according to the regulations, and things happened afterwards we had no influence on."
Kicker reported that Bremen have been trying to find a solution since Tuesday, but have so far been unable to get an answer.
The Bundesliga club have said they will not play their new signing should he not be cleared by the DFB before Friday's kick-off.
"We can't take this risk," the club said. "A protest might be lodged."
