Tour of California organizers have rejected the entries of Rock Racing riders Tyler Hamilton, Santiago Botero and Oscar Sevilla, who have been linked with the Operation Puerto doping probe in Spain.
The trio have been the center of a war of words between Rock Racing team owner Michael Ball and AEG, the corporate owner of the race which started Sunday afternoon with a time-trial prologue.
AEG said the 17 teams signed up for the third edition of the event agreed they would not field any rider not approved by the International Cycling Union (UCI).
On Saturday, Ball had indicated he didn't think the three riders in question were covered by that agreement.
"This is not a decision governed by the agreement," he said in a statement. "There is no open investigation. AEG is acting irrationally to the detriment of the sport."
Andrew Messick, AEG's director of sports, called Ball's comments "disengenuous."
"We have communicated our rules to Rock Racing, and the other 16 participating teams, in plain language," he said.
America's Hamilton has returned to racing after a two-year ban for blood doping during the 2004 Tour of Spain.
Colombia's Botero and Spain's Sevilla have both been linked to the Operation Puerto blood-doping investigation in Spain.