Ecuadorian sprinter Alex Quinonez, who won bronze in the 200m at the 2019 world championships in Doha, is set to miss the Olympics after being provisionally suspended Thursday by the Athletics Integrity Unit (AIU) for dope-testing irregularities.
The AIU said the 31-year-old sprinter was being suspended for "breach of his whereabouts obligations".
They did not expand on the irregularities other than to say that his case had been submitted to the disciplinary court.
The Olympics, postponed from 2020 because of the pandemic, are due to begin in Tokyo on July 23.
Quinonez has a best time of 19.87sec for the 200m and collected bronze at the 2019 Doha worlds behind winner Noah Lyles and silver medallist Andre de Grasse.
The AIU also announced the temporary suspension of Brazilian discus thrower Fernanda Martins, sixth in the last worlds, for a positive test for the anabolic agent ostarine.