By Julien Pretot
ST ETIENNE France (Reuters) - A Tour de France yellow jersey holder will always be grilled about doping and Vincenzo Nibali was no exception on Thursday, having to defend his choice to work with former doper Alexandre Vinokourov.
Nibali joined Astana last year from Liquigas and fell under the guidance of Kazakh Vinokourov, who served a two-year ban after being found guilty of blood doping on the 2007 Tour de France.
Vinokourov came back to the sport and won the 2012 Olympic title in London before taking over as Astana manager.
Kazakh-funded team Astana have a tainted reputation since their first year in 2007, when Vinokourov was kicked out of the Tour following his doping offense.
It was also the team Spain's Alberto Contador was riding for in 2010 when he tested positive for a banned anabolic agent.
But Nibali believes things have changed as he works with sports director Giuseppe Martinelli - the one who led the disgraced Marco Pantani to his Giro d'Italia title in 1998.
Quizzed about his choice to work with Vinokourov and Martinelli after the 12th stage of the Tour de France on Thursday, Nibali said: "I could not say anything about Martinelli, with whom I have a good relationship.
"It is thanks to him that I have joined Astana."
Martinelli, who was Pantani's and Contador's sports director, has not been directly linked to doping, though.
When leaving Liquigas, Nibali also took with him his long-time coach Paolo Slongo.
"It was important that we hired him (at Astana) because I worked a lot with him when I was young," said Nibali, who has a 2:23 lead over second-placed Richie Porte of Australia.
After the Lance Armstrong scandal, Nibali believes the peloton should look forward.
"Mistakes were made by a lot of riders," he said.
"We need to leave these mistakes in the past and give their chance to the young riders.
"There are in and out-of-competition controls in cycling, there is the biological passport (since 2008).
"I came to Astana to be part of a group that could take me to the top in the Giro, in the Vuelta and in the Tour. There will always be idiots. I won't speak for the whole peloton but something has been done to clean up this sport."
Should he wear the yellow jersey in Paris on July 27, Nibali will become the sixth man to win all three grand tours after Frenchmen Bernard Hinault and Jacques Anquetil, Italy's Felice Gimondi, Belgian Eddy Merckx and Contador.
(Reporting by Julien Pretot; Editing by Rex Gowar)