David Millar has been banned from this year's Tour de France after a police investigation into doping offences in his Cofidis team.
Millar has denied any wrongdoing
Millar, who has never failed a dope test, was detained by police on Tuesday after team-mate Philippe Gaumont said he had taken banned substance EPO.
He denies the accusation but Tour chief Jean-Marie Leblanc barred him saying he wanted a "transparent peloton".
The Fassa Bortolo, Domina Vacanze and Saeco teams face similar penalties.
Leblanc, the Tour's director-general, told Associated Press that the teams involved had been warned some time ago that some of their riders may be banned.
"Eight days ago, we warned their leaders that we didn't want riders implicated (in probes) on the Tour. At Cofidis, that concerns Cedric Vasseur and Millar," he said.
"We don't want to pollute the Tour."
Millar is the most high-profile victim of the Tour's decision to ban all riders under investigation.
But his camp were tight-lipped over the doping allegations.
His sister Fran told BBC Sport: "Everything at the moment is speculation. He will see the judge [in Paris, who is leading the investigation] next week but, other than that his lawyers have advised us to say nothing."
This is part of a lengthy investigation into Cofidis after Gaumont admitted in January taking EPO and subsequently accused Millar and his team-mates of also taking banned substances.
Millar, the world time trial champion, who had been putting together his final preparations for this year's Tour, was taken into custody while dining at a Biarritz restaurant on Tuesday.
A police spokesman said: "Millar has been placed under investigation. He was detained at the request of the investigative magistrate."
Cofidis have been under investigation since seven of its riders - including Gaumont and Robert Sassone, Mederic Clain and Marek Rutkiewicz - were charged with doping offences.
They have all left or been sacked by the team since.
Former physio Boguslaw Madejak and an ex-manager of their third division team, Oleg Kozlitine, have also been sacked after the Paris judge investigating the case pressed charges.