Vincenzo Nibali teammate Astana Lars Boom to start Tour de France

Tour de France champion Vincenzo Nibali`s Dutch teammate Lars Boom will start the 2015 race, his Astana team confirmed Saturday.

Boom had returned a low level of cortisol in an unofficial test conducted by the Movement for Credible Cycling (MPCC) earlier this week.

Under MPCC rules, which are not binding, Astana are obliged to stand down Boom for a period of eight days but after failing in their request to the International Cycling Union (UCI) to bring in a replacement, the Kazakh team decided to let the 29-year-old start.

"The MPCC oblige a rider to be replaced if his cortisol level is too low. We wanted to change riders but unfortunately the UCI said no," said Astana manager Alexandre Vinokourov.

"(Alessandro) Vanotti came this morning to replace Boom if need be. But we can`t change riders after the manager`s meeting on Friday morning (at 1030 local time). The rider`s test results arrived at 1430."

MPCC rules state that the rider must be rested for his own health.

However, the UCI and the World Anti-Doping Agency (Wada) do not consider a low cortisol reading to be a problem, therefore there is no doping violation.

A low cortisol level can be produced by the use of glucocorticosteroids, an anti-inflammatory drug that can allow riders to break through the pain barrier.

However, it can also be caused by fatigue, while the use of glucocorticosteroids can produce fatigue and increase the risk of injury.

"According to the medical team there is no danger to the rider`s health so he can start the race with us," added Vinokourov, who once served a two-year doping ban himself as a rider.

"It`s clear and honest, we`ll start the race with nine riders. I can`t start the race with eight."

Boom won last year`s fifth stage on the cobbles and will be an important teammate for Nibali over the first week of this year`s edition, including Tuesday`s very similar cobbled fourth stage.

He will also be vital for the team during the stage nine team timetrial and if Astana were to start that without a full compliment of numbers, it could affect Nibali`s overall hopes.