PSG host relegation battling Le Havre on Saturday
The scientific review will be initiated next year, WADA said on Tuesday. Cannabis is currently prohibited in competition and will continue to be in 2022, it added.
Richardson tested positive for a chemical found in cannabis during the US Olympic Track & Field trials in June, which wiped out her trial results. She was also hit with a one-month suspension.
The 21-year-old, who had been seen as a top contender in the 100 metres, has said she used cannabis to help cope with the death of her mother.
The suspension sparked an outpouring of sympathy and calls for a review of anti-doping rules, including by the US Anti-Doping Agency.