This claim comes from a parody social media account. The runner actually replacing Sha'Carri Richardson on the Olympic team is Jenna Prandini, who came in fourth during the 100-meter trials.
Richardson was suspended during the U.S. Olympic team trials due to the discovery of marijuana-related substances in her system. She accepted the suspension, but it means she will not represent the United States in the Tokyo Olympics.
"Rebecca Washington" is not recorded as a runner in the U.S. Olympic trials. A photo in a social media post is a digitally manipulated image of Prandini, falsely identified in the post as Rebecca Washington.