Gelsenkirchen threatens legal action against Munich's club if suspicions that they illegally negotiated with goalkeeper Manuel Neuer are confirmed.
The contract of the German national team member with Schalke will expire in a year and a half. Negotiations for its extension are not taking place, as the footballer has indicated his desire to leave.
It is said that Neuer has already reached an agreement with Bayern team, where he will replace the veteran Hans Jorg Butt.
"If such an agreement really exists, then it is illegal," said Schalke president Clemens Tonnies. "If these rumors are confirmed, we will take legal action."
The goalkeeper himself said he cannot guarantee that he will stay in Gelsenkirchen until his contract expires: "I cannot confirm that - every story has two sides.
"But there will be no Christmas presents for the fans. I will not give in to pressure."