Simone Biles has revealed why she withdrew from Tuesday's (July 27) team finals in Tokyo.

At a press conference with all four members of the US gymnastics team — following their silver finish — Simone confirmed her decision to step away was due to mental health concerns.

"Whenever you get in a high-stress situation, you kind of freak out," Simone said, per CNN. "I have to focus on my mental health and not jeopardize my health and wellbeing." She added, "We have to protect our body and our mind."

"It just sucks when you're fighting with your own head," Simone continued. "[We're] not just athletes, we're people at the end of the day."

Simone went on to recall how she told her coaches she needed to step away. “I was like, ‘I think the girls need to do the rest of the competition without me,’” she said, per The Guardian. “And they were like, ‘I promise you, you’re fine. We watched you warm up.’ And I said, ‘No, I know I’m going to be fine, but I can’t risk a medal for the team, so I need to call it.’ And you usually don’t hear me say things like that because I’ll usually persevere and push through things, but not to cost the team a medal. So they were like, ‘OK, well, if Simone says this and we need to take it pretty serious.’ And so, I had the correct people around me to do that.”

“Today has been really stressful," Simone admitted. "We had a workout this morning. It went OK. And then just that five-and-a-half-hour wait, I was just like, shaking. I could barely nap. I’ve just never felt like this going into a competition before. And I tried to go out here and have fun and warm up in the back when a little bit better. But then once I came out here, I was like, no, [the] mental is not there. So I just need to let the girls do it and focus on myself.”

The Olympian noted that the team plans to have a "mental rest day" tomorrow (July 28).

Earlier in the day, the reigning Olympic champion left the team competition after struggling to land a vault.

"Simone has withdrawn from the team final competition due to a medical issue," USA Gymnastics spokeswoman Carol Fabrizio told USA Today. "She will be assessed daily to determine medical clearance for future competitions."

The gymnastics superstar exited the competition floor with the team's medical trainer moments after she struggled to land a vault — she bailed on an Amanar, one of her more difficult vaults — during the team's first event of the day.