Christian Coleman will try and have his ban from athletics overturned at the Court of Arbitration for Sport (CAS).
The 100m World Champion was banned for two-years by the Athletics Integrity Unit (AIU) in October for missing three drugs tests in a 12-month period.
Coleman had disputed the second and third of those whereabouts failures, saying he was Christmas shopping on December 9 2019 and was unaware of an attempt to test him until the following day.
He's set to miss next year's rearranged Olympic Games in Tokyo as a result.
There is no suggestion that Coleman has ever taken a performance enhancing substance.
Regarding his repeated missed tests, the AIU branded Coleman "careless, perhaps even reckless".
CAS say that Coleman has filed an appeal with them, seeking his two-year ban be set aside or reduced.
The Court says that "arbitrations are in progress and the parties will exchange written submissions in the coming weeks."
World Athletics have also taken a case to CAS, relating to Salwa Eid Naser.
The AIU handed down a two-year suspension to the Bahraini 400m runner following four missed tests in 2019.
The World Athletics Disciplinary Tribunal since ruled that one of those violations should not have stood, meaning Eid Naser would escape a ban as three missed tests did not fall in the one twelve-month window.
World Athletics are seeking that Tribunal ruling be set aside, and replaced with a new decision in which Salwa Eid Naser is found to have committed an ADRV (anti-doping rule violation) and sanctioned with a two-year period of ineligibility.