Italian rider Alessandro Ballan, whose name has been cited as part of a doping probe in Italy, was on Friday suspended by his BMC team along with teammate Mauro Santambrogio.
Ballan, the 2008 world champion, had been due to compete in Sunday's Paris-Roubaix classic in France, a race in which he had twice finished third.
"We hope to get more information," said BMC team boss Jim Ochowicz, who explained that the investigation related to events before the two riders joined the American team and were with Italian outfit Lampre.
"But we've already made the decision to withdraw the two (riders) from competition. That doesn't presume their guilt regarding the investigations being undertaken in Italy. It's up to the pair to defend themselves personally."
The public prosecutor in Mantua in the northern region of Lombardy announced on Thursday he had opened an investigation into 35 people suspected of involvement in doping offences related to cycling.
According to the daily Gazzetta dello Sport, those being investigated include cyclists, trainers and owners of professional teams, mostly linked with Lampre. The newspaper claimed Lampre manager Giuseppe Saronni, as well as Damiano Cunego, the 2004 Tour of Italy winner, and former team member Ballan were among those being probed.
According to Italian media, the investigation centres around the actions of a local pharmacist, Guido Nigrelli, although prosecutor Antonio Condorelli refused to comment on his alleged involvement.
Condorelli explained that the process was more about the trade in doping substances rather than the use of them, and added that professional cycling had a secondary role.
"The line of inquiry relates moreover to the commercialisation of doping substances rather than who uses them, and extends to foreign shores, although I have not yet made contact with those authorities," he said. "Our investigation into doping is not important for the professional sportsmen implicated but for the fact that the banned substances have been diffused amongst amateur cyclists."
© AFP 2010