Reigning world 100-meter champion Christian Coleman is set to miss the Tokyo Olympics after being banned for two years by the Athletics Integrity Unit (AIU).
The independent body, which combats doping, had provisionally suspended the 24-year-old in June for a "whereabouts failure" and upheld its decision on Tuesday.
The World Anti-Doping Agency's (WADA) "whereabouts" system requires athletes to let anti-doping officials know where they'll be for one hour every day, as well as details of overnight accommodation and training venues.
If an athlete fails to do so and commits a "filing failure" three times over a 12-month period, they could face punishment.
The American sprinter admitted he missed a drugs test on December 9, 2019 -- the third missed test in the space of a year -- but alleges he was set up by the anti-doping body.
Coleman said he had been Christmas shopping "five minutes away" but had no idea a tester had visited his address for one of the tests.
The AIU said shopping receipts showed Coleman was out of the house during the allotted hour and that officers had knocked on his door every 10 minutes without answer.
"Unfortunately, we see this case as involving behaviour by the Athlete as very careless at best and reckless at worst. In those circumstances, we impose a two-year ban," read the AIU disciplinary report.
The AIU said Coleman could appeal the decision to the Court of Arbitration for Sport and confirmed there was no suggestion he had ever taken a prohibited substance.
Coleman's representatives called the decision "unfortunate" and confirmed he would immediately appeal it.
Coleman's other two failures occurred January 16 and April 26 last year.
The sprint star, who has consistently denied ever taking drugs, only narrowly avoided a ban last year after three violations of the "whereabouts" rules across 2018 and 2019. However, his case was dropped because of a technicality over dates.
The decision allowed him to compete at the World Athletics Championships in Doha last September where he claimed victory in the 100m and men's 4x100-meter relay.
Coleman will not be eligible to compete again until May 13, 2022.
The 2020 Tokyo Summer Olympics, delayed because of the pandemic, are set to begin July 23, 2021.