Marina Arzamasova, the 2015 World 800m champion, was provisionally suspended for the presence of an illegal anabolic agent.
Arzamasova, 31, ranks outside the top 100 in the world this year in the 800m, returning from having her second daughter in 2018.
She followed her 2015 World title, the last major outdoor title not won by Caster Semenya, by placing seventh at the Rio Olympics and getting eliminated from the heats of the 2017 Worlds.
The favorite for worlds in a month is American Ajee Wilson, who is second-fastest in the world this year behind Semenya.
Semenya, as well as the Rio silver and bronze medalists, are barred from competing in women’s races between the 400m and the mile under the IAAF’s new testoterone caps.
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