Luxembourg's Frank Schleck, a former podium finisher, quit the Tour de France Tuesday after testing positive for a banned diuretic, his RadioShack team told AFP. Schleck, who finished third in 2011, is currently racing the 99th edition with the RadioShack team run by Johan Bruyneel. His positive test for a banned diuretic was announced earlier by the International Cycling Union (UCI). RadioShack spokesman Philippe Maertens earlier told AFP that "Schleck has left the race".

A statement from the team added: "Our team attaches great value to transparency. Because of this... the team has decided to immediately withdraw Frank Schleck from the Tour de France." Earlier, a statement issued by the UCI said 32-year-old Schleck had been informed of an "Adverse Analytical Finding (presence of the diuretic Xipamide based on the report from the WADA accredited laboratory in Chatenay-Malabry) in the urine sample collected from him at an in competition test at the Tour de France on 14 July 2012."

Schleck "has the right to request and attend the analysis of his B sample", added the UCI. RadioShack said the substance "was not present in any of the medicine that the team uses".

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 ineligiblity".

A second violation would incur "two years ineligibility", in other words a two-year ban, while a third violation would incur a "lifetime ban".

The UCI explained: "The UCI Anti-Doping Rules do not provide for a provisional suspension given the nature of the substance, which is a specified substance."

RadioShack, meanwhile, said it was "the right thing to do" to take Schleck off the race "to ensure the Tour de France can go on calmly and that Frank Schleck can prepare his defence in accordance with the legal timing to do so". The UCI said Schleck was allowed "four days for him to have his B sample analyzed".

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 edema and hypertension.