American sprinter Sha’Carri Richardson will not be selected for the US 2020 Olympic 4×100-metre relay team after she accepted a one-month ban for testing positive for cannabis.

The 21-year-old, who streaked to victory in the 100m at the US Olympic trials in June, was expected to be one of the biggest drawcards at the upcoming Tokyo Games.

Her supporters had hoped she could still compete in the relay event after the United States Anti-Doping Agency (USADA) confirmed the suspension last week.

“We are incredibly sympathetic toward Sha’Carri Richardson’s extenuating circumstances and strongly applaud her accountability – and will offer her our continued support both on and off the track,” USA Track & Field said in a written statement.

Richardson said in an NBC interview last week she used the banned substance to cope with the death of her mother.

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The women’s 100m event in Tokyo starts on July 30, two days after her ban ends, but she is unable to compete in the event as her suspension wiped out her results at the trials.

Selection to the relay team was her only remaining chance of competing at the Games.

“All USATF athletes are equally aware of and must adhere to the current anti-doping code, and our credibility as the National Governing Body would be lost if rules were only enforced under certain circumstances,” USATF said.

The organisation added it believes the World Anti-Doping Agency rules regarding THC “would be re-evaluated.”

“While our heartfelt understanding lies with Sha’Carri, we must also maintain fairness for all of the athletes who attempted to realise their dreams by securing a place on the US Olympic Track & Field Team.”