Astana, the team of defending champion Vincenzo Nibali, invited further scrutiny over its moral code after announcing Dutch rider Lars Boom will start the Tour de France on Saturday.
Boom, 29, has not failed a drugs test, but as Astana are members of the Movement for Credible Cycling (MPCC) he should, under the organisation's voluntary code, be removed from competition for a period of eight days after he returned cortisol levels under the normal level.
The UCI, cycling's world governing body, regulations stated Boom could not be replaced on the eve of the race and he will now roll down the start ramp for Saturday's opening 13.8-kilometre time-trial after the Kazakh squad sought medical advice.
Low cortisol levels could indicate the use of the steroid cortisone, which is permitted in some circumstances, with prior approval.
Astana said Boom's result was "the consequence of a long-standing and well-known application of anti-asthma therapy by the athlete and is not a violation of UCI rules and regulations".
It means Astana, who risked having their WorldTour licence revoked earlier this year when the UCI asked its licence commission to take action after a number of anti-doping violations in 2014, could be excluded from the MPCC.
Not all leading Tour teams are members. None of the teams led by Nibali's main rivals - Alberto Contador's Tinkoff-Saxo, Chris Froome's Team Sky and Nairo Quintana's Movistar - for glory in Paris this month belong to the group.
Astana said in a statement on Saturday: "Astana Pro Team will start the 2015 Tour de France with nine riders, including Dutch cyclist Lars Boom.
"Astana Pro Team asked the UCI to allow a replacement rider in place of Boom, and received confirmation from the UCI that as a low cortisol result is no risk to the health of the rider, therefore there are no valid grounds for a late substitution."
His condition will be closely monitored, it added.