"The news about the Danish rider today has no bearing one way or the other" on Discovery's sponsorship of the U.S. team, executive vice president of communications and corporate affairs David C. Leavy said.
In January, Discovery declined to renew its three-year agreement to back the team. That means this is its last year to sponsor the team, which won the Tour de France in 2005 behind Lance Armstrong.
Riis' admission came after several other riders admitted last week to doping, including former sprint star Erik Zabel. Earlier this month, Ivan Basso, the 2005 runner-up to Armstrong, left the Discovery team after Italian authorities reopened a doping investigation. And last year’s winner, American Floyd Landis, still could see his title stripped due to doping.