Deajah Stevens, a Rio Olympic sprinter, and fellow Tokyo Olympic hopeful Gabby Thomas were provisionally suspended for drug-testing whereabouts failures.
Stevens, seventh in the 2016 Olympic 200m, and Thomas, the 2018 NCAA Outdoor Championships 200m runner-up with Harvard, had their cases referred to disciplinary tribunals.
A suspension for whereabouts failures means any combination of three missed drug tests and/or filing failures in a 12-month period. A filing failure could mean incorrectly filling out forms to tell drug testers where an athlete can be found, or not submitting quarterly forms at all.