Simone Biles is out of the team final.

Simone Biles, the American gymnastics star, has pulled out of the team competition at the Tokyo Olympics, according to Carol Fabrizio, a U.S.A. Gymnastics spokeswoman. Fabrizio did not offer a reason for the withdrawal.

U.S.A. Gymnastics issued a statement that said: “Simone has withdrawn from the team final competition due to a medical issue. She will be assessed daily to determine medical clearance for future competitions.”

Biles, considered the greatest gymnast in history who said this week that she felt the “weight of the world on her shoulders,” left the competition floor on Tuesday after performing on the first apparatus of the night, the vault. She had bailed out of the vault she had planned to do — a Yurchenko with 2½ twists, watering it down to 1½ twists and then stumbling on the landing. Her score of 13.766 points was extremely low for Biles, the best vaulter in the world who can land skills so difficult and daring that no other woman even trains to do them. Without Biles’s usual high score on the vault, the United States finished the first of four events already more than a point behind Russia.

Afterward, Biles left the competition floor with a team trainer, as her coach, Cecile Landi, gathered the three remaining gymnasts and walked them to the next apparatus. The team’s plan had been for Biles to compete on the uneven bars with teammates Grace McCallum and Sunisa Lee, but it had to improvise. Jordan Chiles took Biles’s place on the event.

Upon returning to the floor, Biles rejoined the team and hugged each of her teammates. While wearing a white Team USA sweatsuit, she watched them perform their routines from the sideline, cheering loudly

The team continued the competition without her, still hoping to win the gold medal for the third consecutive Olympics. But even though each of the three American competitors put forth solid, and in one case spectacular, uneven bar routines, the U.S. team was 2.5 points behind Russia halfway through the event.