Sha’Carri Richardson, who missed the Tokyo Games, asks why a Russian skater can compete after failing a doping test.

She asked for a “solid answer” on the difference between Valieva’s case and her own, noting that she too had been expected to win a medal. “The only difference I see is I’m a black young lady,” she wrote.

Richardson questioned why Valieva was allowed to compete despite doubts about her eligibility, when Richardson had been forced by U.S. officials to skip the Olympics altogether.

In its ruling on Monday, the I.O.C. said that should Valieva win a medal, no ceremony would be held until her case is resolved. Though her test sample was taken on Dec. 25 at the Russian championships, the results were not confirmed until Feb. 7, after she had competed in the team figure skating competition, Russian antidoping officials have said.

Antidoping experts disagree on whether trimetazidine could have enhanced Valieva’s performance. Valieva’s coach, Eteri Tutberidze, told Russia’s state-run TV network Channel One on Saturday that, even though there are still many unanswered questions about the case, “we are absolutely confident that Kamila is innocent and clean.”

Marijuana is considered a performance-enhancing drug by the World Anti-Doping Agency and is banned on race days, but not outside of competition. Though research on the drug is limited, it can have energizing or sedating effects, depending on the strain; marijuana could be used, for example, as a relaxation aid before intense competitions.

Richardson’s case has led to calls to reconsider marijuana’s status as a banned substance, since it is legal in many states. She said she had used the drug to cope with the death of her mother.