Former world cycling champion Tom Boonen has been barred from this year's Tour de France after testing positive for cocaine.
Tour organizers say the rest of Boonen's Quick Step team can still compete in the race.
The Belgian rider apologized to his fans Wednesday in Brussels. Belgian prosecutors opened a probe Tuesday into possible cocaine possession by Boonen.
Boonen read a brief statement to reporters but did not specifically confirm or deny allegations that he had taken cocaine just ahead of a surprise out-of-competition doping test late last month, which found traces of the drug in his urine sample.
"I am not going to defend myself here today, but I have caused my family, friends and team pain and I apologize for that," Boonen said. "I have been in the news in a negative way lately. I am not perfect and will accept the consequences."
The cyclist has garnered celebrity status in Belgium, where cycling is one of the most watched and followed sports. He urged his fans "to keep faith" and said he would be back soon after a break from racing.
News that Belgian prosecutors opened a probe Tuesday into suspected cocaine use and possession dominated newscasts in Dutch-speaking Flanders and the story headlined most Belgian dailies on Wednesday.
Prosecutors said the investigation could last months but warned that Boonen could face a jail sentence and/or fines for using or possessing the drug.
Penalties for cocaine possession in Belgium can vary from three months to five years in jail, along with fines of up to $155,000.
Boonen, the 2005 world champion, earned his first green jersey as the best sprinter in last year's Tour de France.
Quick Step manager Patrick Lefevre said his team would continue to back Boonen.
"After discussions with the sponsor we decided to reconfirm our trust in Tom Boonen," Lefevre said. "The easiest thing is to dump someone if they did something wrong ... We know the athlete Tom Boonen has done a lot for our team in the last six years and we hope in the coming three years he can still do more for the team."
Lefevre said the team's main sponsor Quick Step agreed to continue backing the team for three more years despite Boonen's alleged drug use.
Organizers of the Tour of Switzerland, a warm-up for the Tour de France, said Tuesday that Boonen was no longer welcome to start the race on Saturday.
Belgian cycling union director Tom Van Damme said Boonen had already done damage to his image and more harm to the sport.
"Boonen risks losing more of his hero status," Van Damme told daily De Morgen. "Children who dream of a cycling career will be unable to digest this."
The cyclist ran into trouble with police last week when he was caught speeding in a car while under the influence of alcohol.
Boonen has so far not been charged. He was released after questioning by authorities in Turnhout on Monday over the results of the doping test.
The test was conducted on May 25 between two races, the Paris-Roubaix and the Tour of Belgium, when Boonen was taking time off, reports said.
However, the International Cycling Union said Tuesday Boonen was unlikely to face punishment from the governing body because the test came outside of competition.
The World Anti-Doping Agency classifies cocaine as a stimulant but it is only prohibited if the substance is taken in-competition.