UK Anti-Doping (UKAD) has upheld former Team Sky rider Jonathan Tiernan-Locke's two-year ban after irregularities were found in his biological passport.
Tiernan-Locke withdrew from racing in September after being questioned by the International Cycling Union (UCI) over a discrepancy in his blood data.
He blamed the finding on an "alcoholic binge" and subsequent dehydration but the UKAD said he had used "a prohibitedsubstance (an erythropoiesis-stimulating agent) and/or prohibited method (blood doping) to boost his levels of haemoglobin".
"This was based on expert opinion on the conclusions drawn from a blood sample taken on 22 September 2012 under the UCI Athlete Biological Passport (ABP) programme," the UKAD added.
"This sample was assessed against four further samples taken to build a profile of the rider's blood."
The UKAD said Tiernan-Locke, 29, had failed to sufficiently explain the abnormal values, which were taken before he joined Team Sky.
He is banned until the end of 2015.
Mark Cavendish will not take part in the Vuelta a Espana despite returning to racing last week.
The 29-year-old Manxman had been included in a long-list of potential participants by organisers of the Spanish Grand Tour, but was not in the final nine-man Omega Pharma-Quick Step squad released.
Cavendish, who was hurt in a crash on the opening stage of the Tour, returned to action in last week's Tour de l'Ain but is not yet in the sort of shape needed for a three-week Grand Tour.
Chris Froome will return to cycling in Spain this weekend after being forced to abandon the Tour de France last month. "This is exactly the sort of challenge that I need after the disappointment of withdrawing from the Tour de France," Froome said after his Vuelta a Espana participation was confirmed.