Transgender swimmer Lia Thomas, who made national headlines in 2022 after winning an NCAA individual title, will not be allowed to compete in elite women’s races, including the 2024 Olympics, after the Court of Arbitration for Sport ruled this week that she lacks standing for her challenge to the rules of swimming’s world governing body.

The ruling comes just days before the U.S. Olympic swimming trials, which begin Saturday.

CNN has reached out to Thomas’ attorney for the swimmer’s comment.

Thomas, 25, had in January filed legal paperwork against World Aquatics, swimming’s governing body based in Switzerland, for its policy that restricts transgender athletes from competing in most elite women’s aquatics competitions.

The policy dictates male-to-female transgender athletes would only be eligible to compete in the women’s categories if they transition before the age of 12 or before they reach stage 2 of the puberty Tanner Stages.

World Aquatics officials said in a statement the decision this week is “a major step forward in our efforts to protect women’s sport.”

“World Aquatics is dedicated to fostering an environment that promotes fairness, respect, and equal opportunities for athletes of all genders and we reaffirm this pledge,” officials said. “Our policies and practices are continuously evaluated to ensure they align with these core values, which led to the introduction of our open category.”

The three-member Court of Arbitration for Sport panel found Thomas was not eligible “for the time being” to participate in World Aquatics competitions and only eligible for USA Swimming events that do not qualify as elite events. It also said national federations don’t have the authority to modify the application of a world governing body’s rules.

As a swimmer on the women’s team at the University of Pennsylvania, Thomas became the first transgender athlete to win an NCAA Division I title after winning the women’s 500-yard freestyle event in March 2022. The NCAA championships fall outside the purview of World Aquatics.

A few months later World Aquatics ratified its updated gender policy, which went into effect in March 2023, according to the 24-page arbitral award. It created an open category for transgender athletes at a World Cup event in Berlin in October for “all sex and gender identities.”

World Aquatics oversees competitions in swimming, artistic swimming, open water swimming, water polo, diving and high diving. USA Swimming is the national governing body for swimmers and a member of World Aquatics.

The ruling comes just before the U.S. Olympic swimming trials, which begin Saturday.

In May 2022, Thomas told ABC’s Juju Chang, “It’s been a goal of mine to just swim at an Olympic trials for a very long time and I would love to see that through.”