German cyclist Patrik Sinkewitz, who tested positive in June for elevated levels of testosterone, was fired Tuesday by his T-Mobile team after refusing to have his backup sample tested.
T-Mobile dismissed Sinkewitz after the German Cycling Federation said the 26-year-old rider declined to have his B-sample analyzed.
"For the team, this means that it is a positive doping case," T-Mobile spokesman Christian Frommert said from Berlin. "That means he will be fired by the team."
Sinkewitz admitted to "incorrect conduct" just hours after being dismissed.
On Tuesday, Sinkewitz said he had obtained Testogel, a substance he used on the skin to balance out a testosterone deficit.
The substance "is supposed to aid better recuperation during hard training exercises," he said in a statement on his website.
"Without thinking, or simply in great stupidity, I had applied Testogel secretly to my upper arm at the training camp in France on the evening before the doping test," Sinkewitz said, without specifying whether he knew the substance was banned. "I did it instinctively and without thinking about the possible consequences."
T-Mobile had initially suspended Sinkewitz after he tested positive during training on June 8 — a month before the start of the Tour de France. He competed in the race until he crashed into a spectator during the eighth stage on July 15.
T-Mobile said in a statement that its sporting director, Rolf Aldag, now expects a "complete and comprehensive explanation" from Sinkewitz.
"Patrik needs to come clean on everything, so some light can be shed on this affair," he said.
Cycling a hotbed for controversy
Later Tuesday, German mineral water producer Foerstina said it was ending its sponsorship contract with Sinkewitz with immediate effect.
Sinkewitz had signed the International Cycling Union's new anti-doping charter that commits riders to promise they are not involved in doping and agree to pay a year's salary on top of a two-year ban if caught doping.
Hesaid he wants to help bring about "a new cycling without doping" in future.
His case is the latest to shake German cycling in the past few months.
Several former riders for Telekom, now renamed T-Mobile, admitted using performance-enhancing drugs in the 1990s, including Bjarne Riis, a Dane who won the Tour de France in 1996.
Jan Ullrich, who won the 1997 Tour, has denied any wrongdoing, but retired in February after being implicated in the Spanish blood-doping scandal known as Operation Puerto.
T-Mobile's current anti-doping program is considered among the most rigorous in cycling.
The July 18 announcement of Sinkewitz's positive test prompted Germany's two main public television channels, ARD and ZDF, to drop their live coverage of the Tour in mid-race.