The International Cycling Union (UCI) announced that the Spaniard had been provisionally suspended in August, having failed a test.

Sanchez, winner of the the road race title at Beijing 2008, tested positive for banned growth hormone GHRP-2.

He failed during an out-of-competition test on August 9.

Analysis of the 39-year-old’s B sample at the World Anti-Doping Agency accredited laboratory in Lausanne confirmed the positive.

"BMC Racing Team was previously informed by the UCI of a potential anti-doping violation for the presence of GHRP-2 and its metabolite, in an out-of-race anti-doping control for Samuel Sánchez Gonzalez," a BMC Racing statement read.

"In accordance with BMC Racing Team’s zero tolerance policy with respect to doping violations and UCI regulations, Sánchez was immediately suspended from BMC Racing Team.

"At the request of Sánchez, his B sample was analysed at the WADA accredited laboratory in Lausanne, Switzerland.

"The analysis of Sánchez’ B sample confirmed the presence of GHRP-2 and its metabolite, as found in his A sample.

"At that time, Sánchez’ contract with the team was terminated with immediate effect."

The positive test ruled Sanchez out of BMC Racing’s team for the Vuelta a España after he had been named as a replacement for Loïc Vliegen.

Sánchez has won individual stages at the Vuelta on five occasions but could not defend his Olympic title at London 2012 due to a crash at that year's Tour de France.

The Spaniard protested his innocence, after the positive test was initially announced.

He could face the prospect of a lengthy ban, with Italian rider Stefano Pirazzi having received a four-year sanction earlier this month after testing positive for the same substance before the Giro d’Italia.

Sánchez had been expected to retire after the Vuelta a España.