Simone Biles, reigning Olympic gymnastics champ, is out of the women’s team final in Tokyo.

“Simone Biles has withdrawn from the team final competition due to a medical issue,” a USA Gymnastics spokesperson said in a statement early Tuesday.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

Speaking with NBC broadcasters on Tuesday, per UPI’s Alex Butler, a TEAM USA coach said that the decision to withdraw was not due to an injury but was instead spurred by a “mental issue [Biles] is having.”

As Torrey Hart noted in a separate report, Biles had made history when advancing to all six possible Olympic finals, becoming the first woman to do so since 1992. Later this week, Biles is slated to defend her title.

Ahead of the announcement of her withdrawal, Biles reflected on her preparation for finals in an Instagram caption.

“It wasn’t an easy day or my best but I got through it,” she said earlier this week. “I truly do feel like I have the weight of the world on my shoulders at times. I know I brush it off and make it seem like pressure doesn’t affect me but damn sometimes it’s hard hahaha! The olympics is no joke! BUT I’m happy my family was able to be with me virtually. They mean the world to me.”

Ultimately, Tuesday saw the remaining American team—Sunisa Lee, Grace McCallum, and Jordan Chiles—competing in the final three rotations without Biles. The Russian team posted a score of 169.528, per AP, placing them ahead of the U.S. at 166.096.