Sprint sensation Sha'Carri Richardson is in massive doubt for the Tokyo Olympics after reportedly failing a drug test.
The 21-year-old won the 100m at the US Olympic track and field trials last week to stamp herself as a contender for gold in Tokyo.
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However she was abruptly withdrawn from the Diamond League event in Stockholm on Sunday.
It was not immediately clear why Richardson is not competing and her manager did not respond to a request for comment from Reuters.
"I am human," she wrote in a cryptic tweet earlier on Thursday.
According to Tyler Dragon of the Cincinnati Enquirer, Richardson is facing a 30-day suspension after testing positive for marijuana.
Dragon reported that Richardson is expected to be suspended for the 100m at the Olympics, but might get to run on the 4x100 relay.
Sha'Carri Richardson's scintillating showing at US trials
Richardson previously ran the sixth-fastest 100m time in history, setting a personal best of 10.72 last April.
She seemingly set up a headline sprint showdown with Jamaican superstar Shelly-Ann Fraser-Pryce in Tokyo after a dominant display at the US Olympic trials.
The 21-year-old flashed home in her semi in a wind-assisted 10.64 seconds and then backed up to win the final in 10.86.
An over-the-limit tailwind prevented the 10.64 from becoming official and left Richardson only one-hundredth of a second behind Fraser-Pryce's top time of 2021.
The world record of 10.49 was set by Florence Griffith Joyner in 1988.
"She carries such a firecracker," said Richardson's training partner, Justin Gatlin.
"She's capable of running 10.6. I've seen her at practice, and she's capable of running 10.5, actually.
"She can definitely shock the world."
Richardson is as well-known for her colourful hairstyles as her speed on the track.
“It’s loud and encouraging and, honestly, dangerous,” Richardson said when asked why she chose the colour orange for her big night.
“Knowing I’m coming to one of the biggest meets there is, if you’re going to out there and be the best, you need to look the best.”
Richardson said crossing the finish line first was only the second-best feeling of the night.
The best came afterward, when she climbed halfway up the stands at Hayward Field and shared a long hug with her grandmother, Betty Harp, who's also known in the family as “Big Momma.”
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