As a result of these challenges, Ruck performances going into the 2021 season were noticeably below her personal bests set in 2018 and 2019. While she was pre-selected for the 100 m freestyle event at the Olympics based on her 2019 World Championships result, she would subsequently drop out of this event, with her space being taken by Kayla Sanchez, who had finished second at the Canadian Olympic trials, where Ruck had finished fifth. She also qualified to compete in the backstroke events, and was named to the Canadian relay teams.