Bayer Leverkusen's director of sport Rudi Voller says Michael Ballack's agent is not welcome at Saturday's Bundesliga clash with Stuttgart.

Voller has taken exception to Michael Becker's remarks earlier this week that his client has been made a scapegoat by the club for their problems.

He spoke after Leverkusen's general manager Wolfgang Holzhauser admitted that signing Ballack 20 months ago was probably a mistake.

"It is Michael Ballack's duty to speak for himself if he has something to say and not send his agent Michael Becker in his place," said Voller at a heated pre-match press conference.

"As far as Becker is concerned, it is not on what he says about Bayer Leverkusen and that he attacks this club.

"We have told him that today and he has been shown an orange card by us.

"This is the last time that he attacks us like this. It will never happen again, otherwise he will never step foot in our stadium again.

"We would all be well advised to look forwards and get back to concentrating on what matters, which is playing good and successful football."

That is likely to happen without Ballack as he is set to be on the bench again against Stuttgart.

However, Voller expects him to honour the final five months of his contract with professionalism.

"We have high ambitions for this season and we still want to attack at the top," he said. "And for that, we also need Michael Ballack to get fully involved, whether he is playing or not.

"We have all got to pull in the same direction."

That attitude appears to have been assumed by the Stuttgart fans, with around 3,000 following their team to Leverkusen, despite a run of four straight defeats.

"It is sensational the way our fans carry on backing us," said Stuttgart coach Bruno Labbadia on his club's website.

"A bit of dissatisfaction in view of our recent results is understandable, therefore we need something to celebrate.

"But wins don't just happen, we have got to work hard for them."

Vedad Ibisevic will look for his first goal in his second game for the club while Leverkusen could give a debut to new arrival Vedran Corluka.