Frankfurt striker Ioannis Amanatidis has been reprimanded for his criticism of the club's selection policy, according to executive Heribert Bruchhagen.
Last week the Greece international, who has made only two starts this season, blasted manager Michael Skibbe for failing to pick players based upon their performances in training.
Bruchhagen has now revealed that the club has warned Amanatidis of the need to maintain discipline and that he will face sterner punishment if there is a repeat.
"We have been aware of the statements of Ioannis Amanatidis and we feel the statements are wrong in form and content," said Bruchhagen.
"We have made it obvious to Ioannis Amanatidis that he has gone against the rules and interests of Frankfurt.
"We have emphasised he will have to deal with greater consequences in the case of a recurrence."
Amanatidis, 28, is a former captain of Frankfurt and is under contract until the summer of 2012, but struggled with injuries last season.