Simone Biles entered the Tokyo Olympics as America’s biggest star. The 24-year-old Texan had won every all-around national, world and Olympic competition she had competed in since 2013. But on Tuesday, Team USA announced that she pulled out of the team finals because of a “medical issue.” In her absence, the American women had to settle for silver. Russia took the top spot.

The New York Times provides details:

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.

Biles huddled with Team USA’s medical trainer after the vault. They determined she was unable to continue. A teammate replaced her on the uneven bars.

The precise nature of the injury is unclear. Biles stayed on the floor to cheer on her teammates.

“Simone has withdrawn from the team final competition due to a medical issue,” USA Gymnastics said. “She will be assessed daily to determine medical clearance for future competitions.”

ESPN explains, “It remains to be seen whether she will be available for the all-around final on Thursday night and the event finals later in the Games.”

Biles has won five Olympic medals, including 4 golds. She was hoping to lead the American women to their third consecutive Olympic title.