Aprilia MotoGP rider Andrea Iannone has been handed a provisional suspension after testing positive for an anabolic steroid.
Iannone, the winner of the 2016 Austrian Grand Prix, is in the middle of a two-year works contract with Aprilia. His positive test came from a sample taken at the Malaysian Grand Prix.
He has been suspended "until further notice" according to a statement made by the governing body, Federation Internationale de Motocyclisme (FIM).
Iannone can appeal and request that the second sample he would have given in Malaysia can be analysed, and he can be present when it is investigated.
He can also appeal the suspension of his license, which prevents him from competing in "any motorcycling competition or activity", according to the statement.
"The Federation Internationale de Motocyclisme (FIM) has advised Italian Grand Prix rider Andrea Iannone that he is provisionally suspended pursuant to Article 7.9.1 of the 2019 FIM Anti-doping Code (CAD)," the FIM statement read.
It also added: "Mr Andrea Iannone has the right to request and attend the analysis of his B sample.
"Mr Andrea Iannone is provisionally suspended with effect from 17 December 2019.
"He is therefore barred from participating in any motorcycling competition or activity until further notice.
"Under Article 18.104.22.168 CAD, Mr Iannone may request lifting of his provisional suspension.
"Under the World Anti-Doping Code and the FIM Anti-Doping Code, the FIM is unable to provide any additional information at this time."
His positive test marks the first official case of a potential doping violation in the grand prix paddock since 2012 when Moto2 rider Anthony West tested positive for methylhexanamine.
West lodged an appeal to the Court of Arbitration for Sport, but was unsuccessful and had a year and a half worth of Moto2 results voided retrospectively.
Iannone, who had joined Aprilia to replace Scott Redding in the previous off-season, had struggled to match the team's incumbent rider Aleix Espargaro for much of 2019, although he seemed to close the gap towards the end of the campaign.
Though he out-qualified Espargaro only once in 17 attempts, he scored a respectable 43 points to the Spaniard's 63 and posted the marque's best finish of the season with sixth place at Phillip Island.
He has previously ridden for Ducati satellite team Pramac, the Ducati works team and Suzuki in a premier-class career that has so far spanned seven seasons.