American champion Sha’Carri Richardson cannot run in the Olympic 100-meter race after testing positive for a chemical found in marijuana.

Richardson won the 100 at Olympic trials on June 19. She told of her ban Friday on the “Today Show.”

Richardson says she smoked marijuana as a way of coping with her mother’s recent death.

She tested positive at the Olympic trials and so her result is erased.

She accepted a 30-day suspension that ends July 27, which would be in time to run in the women’s relays.

USA Track and Field has not disclosed plans for the relay.

The 21-year-old sprinter was expected to face Jamaica’s Shelly-Ann Fraser-Pryce in one of the most highly anticipated races of the Olympic track meet.