In this July 8, 2019, file photo, Ukraine's Dayana Yastremska returns the ball to China's Zhang Shuai (not in frame) during a women's singles match at the Wimbledon Tennis Championships in London. (KIRSTY WIGGLESWORTH / AP)

Ukraine’s Dayana Yastremska has been provisionally suspended after the World Anti-Doping Agency (WADA) found a banned substance in an out-of-competition urine sample, the International Tennis Federation (ITF) said on Thursday.

Yastremska, 20, provided the sample in November and a WADA lab in Montreal found the presence of mesterolone metabolite, an anabolic agent on its Prohibited List.

I’m astonished and under shock, particularly given that two weeks prior to this test... I tested negative at the WTA event in Linz. After this last tournament of the year, I stopped practicing to rest prior to the start of the new season.

Dayana Yastremska, Ukrainian tennis player

“Yastremska was charged with an Anti-Doping Rule Violation under Article 2.1 of the Programme (presence of a Prohibited Substance in a Player’s Sample) and was provisionally suspended with effect from Jan 7,” the ITF said.

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“Yastremska had (and retains) the right to apply to the Chair of the Independent Tribunal convened to hear her case why the Provisional Suspension should not be imposed, but has chosen not to exercise that right to date.”

Yastremska, ranked 29 in the world, denied having used performance enhancing drugs and believes the positive test was the result of a “contamination event”.

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“I’m astonished and under shock, particularly given that two weeks prior to this test... I tested negative at the WTA event in Linz. After this last tournament of the year, I stopped practicing to rest prior to the start of the new season,” she said in a statement.

“Only a very low concentration of mesterolone metabolite was detected in my urine. Given that low concentration and given my negative test two weeks earlier, I have received scientific advice that the result is consistent with some form of contamination event.”

The ITF did not say when Yastremska’s hearing would take place, putting her participation in the Feb 8-21 Australian Open in doubt.