Christian Coleman has been cleared to take part in this month's World Athletics Championships after the United States Anti-Doping Agency (Usada) dropped charges against him on a technicality, a statement said Monday.
US sprinter Coleman, the fastest man over 100m this year, had been facing a two-year suspension after drug-testers were unable to locate him on three separate occasions in a 12-month period.
However Usada said in a statement that after receiving guidance from the World Anti-Doping Agency on how the 12-month window should be calculated, it was withdrawing its case.
"Consistent application of the global anti-doping rules is essential in every case," Usada chief executive Travis Tygart said in a statement.
"In this case we applied the rules to Mr. Coleman in the manner that Usada understands should be applied to any other International-level athlete.
"We must approach every case with the primary goal of delivering fairness to athletes under the rules and providing transparency and consistency in order to build their trust and support for the anti-doping system."
Usada said in its statement it had first recorded a "whereabouts failure" against Coleman on June 6 last year.
A doping control officer had attempted to test the sprinter and discovered that he had failed to update his whereabouts information to accurately reflect his location.
Two more whereabouts failures were also logged on January 16 this year and April 26.
However Coleman argued that under International Standard for Testing and Investigations (ISTI) guidelines, his first missed case should have been backdated to the first day of that quarter - April 1, 2018 - which would mean the dates of the three offences fell outside the required 12-month time frame for a doping offence to have occurred.
In order to avoid future confusion, the rule is being revised with the change expected to take place in 2021.
Usada said it had consulted with Wada to receive an official interpretation of the ISTI rules last week.
"This interpretation was received on Friday, August 30, 2019, and was that the Filing Failure which Usada had recorded in June 2018, should relate back to April 1, 2018, the first day of the quarter in which the failure to update occurred," Usada said in a statement.
"Given these facts, Usada has determined that under the applicable rules, and in order to ensure that Coleman is treated consistently with other athletes under the World Anti-Doping Program, Coleman should not be considered to have three Whereabouts Failures in a 12-month period."
Usada said Coleman had since provided his whereabouts information by the start of each quarter as required and had been tested by the agency on 20 separate occasions.
The sprinter had been due to face a hearing on Thursday which has now been scrapped, Usada said.
The agency said Coleman was free to compete with immediate effect but noted that the decision to withdraw the case could still be appealed by the International Association of Athletics Federations (IAAF).
"Every athlete is entitled to a presumption of innocence until their case is concluded through the established legal process," Tygart said.
"This is certainly the case for Mr. Coleman, who has been found by Usada not to have committed a Whereabouts Violation and is fully eligible to compete under the rules," he added.
Coleman is the fastest man in the world over the 100m and the favourite in that distance heading into the 2019 World Championships in Doha, Qatar. He is also expected to run in the 4x100m Relay and the 200m.
He has run the two fastest 100m of 2019, a 9.85 and a 9.81.