Organisers of the Hamburg Cyclassics say they do not want Alberto Contador or Michael Rasmussen to race in their event.
Contador, who won the Tour de France this year, is not welcome because he was named in the Spanish blood doping scandal of 2006.
He was cleared of any wrongdoing by cycling chiefs and was unlikely to race in Hamburg anyway.
Rasmussen was barred after his Rabobank team sacked him for missing drugs tests and lying about his whereabouts.
Meanwhile, Astana's Andrej Kashechkin has tested positive for blood doping.
Is it right to stop cyclists entering races?
And is progress being made on cleaning up the sport?