Colombian rider Nairo Quintana has denied using a banned substance after he was retrospectively disqualified from the 2022 Tour de France.
Analysis of two blood samples from the 32-year-old showed the presence of banned drug tramadol.
Quintana has now been stripped of his overall sixth-place finish, but has 10 days to appeal against the decision.
“I am totally unaware of the use of this substance, and I deny having used it in my career,” Quintana said.
“With my team of lawyers, we are exhausting all the processes for my defence.”
Because it is a first offence by Quintana, he is still eligible to participate in competition.
However, the Arkea-Samsic rider has confirmed that he will not compete in the Vuelta a Espana, which begins on Friday.
“I will not participate in the Vuelta to assert my reasons before the Court of Arbitration for Sport (Cas),” added Quintana.
“I will return to the race calendar at the end of the season.”
Quintana won that event in 2016, as well as the Giro d’Italia in 2014, and has two second-place finishes in the Tour de France.
Using tramadol is an offence only under the UCI medical rules because of the side-effects which include dizziness, drowsiness and loss of attention.
Though banned since 2019, it does not constitute anti-doping rule violations.