Tour de France chief Christian Prudhomme applauded a decision by the RadioShack team to take Frank Schleck off the race on Wednesday after he tested positive for a banned diuretic.
Schleck, who finished third overall in 2011, was expected to return to his native Luxembourg on Wednesday following questioning by police after his positive test was announced by the International Cycling Union (UCI).
Although UCI rules state Schleck could have started the race's 16th stage from Pau to Bagneres-de-Luchon, Prudhomme said RadioShack had made the right decision in sending Schleck home.
"According to the rules of the UCI Frank Schleck could have started the race today. But, in agreement with his team, it was decided to take him out of the race," Prudhomme said Wednesday.
"It was the right decision, the only possible decision."
Schleck has four days in which to have a B sample analysed.
RadioShack spokesman Philippe Maertens said Tuesday "if his B sample tests positive he would be suspended by the team", while awaiting further investigation.
A statement released Tuesday by the team said: "Our team attaches great value to transparency. Because of this... the team has decided to immediately withdraw Frank Schleck from the Tour de France."
Because Xipamide falls into a special category of substances under the World Anti Doping Code called 'Specified Substances', Schleck has a chance to prove his innocence.
The Code states that when an "athlete can establish that the use of such a specified substance was not intended to enhance sport performance, the period of ineligibility... shall be replaced with the following."
For a first violation athletes face anything from "a reprimand" or, at most, a "one year's ineligibility".
A second violation would incur "two years ineligibility", in other words a two-year ban, while a third violation would incur a "lifetime ban".
Diuretics are not considered performance-enhancing but can be used to help riders lose weight, and therefore perform better in the tough mountain stages of the race.
More ominously, they can also conceal the presence of a banned drug by helping to flush it from the body through increased urination. Xipamide, a diuretic, is normally used for the treatment of oedema and hypertension.
Schleck, whose younger brother Andy was awarded the race victory from 2010 after Spain's Alberto Contador was disqualified for doping, was in 12th place at 9:45 off the pace of race leader Bradley Wiggins of Britain.
Last week Frenchman Remy Di Gregorio of Cofidis quit the race after calls to a supplier of doping products were intercepted by and acted upon by police.