Simone Biles will not defend her Olympic title.

The American gymnastics superstar withdrew from Thursday's all-around competition to focus on her mental well-being.

USA Gymnastics said in a statement on Wednesday that the 24-year-old is opting to not compete. The decision comes a day after Biles removed herself from the team final following one rotation because she felt she wasn't mentally ready.

Jade Carey, who finished ninth in qualifying, will take Biles' place in the all-around. Carey initially did not qualify because she was the third-ranking American behind Biles and Sunisa Lee. International Gymnastics Federation rules limit countries to two athletes per event in the finals.

The organization said Biles will be evaluated daily before deciding if she will participate in next week's individual events. Biles qualified for the finals on all four apparatuses, something she didn't even do during her five-medal haul in Rio de Janeiro in 2016.

Biles spent a portion of Wednesday evening watching American teammates Sam Mikulak and Brody Malone compete in the men's all-around finals. Mikulak, a three-time Olympian, praised Biles' decision.

“We’ve had some conversations (and) she seems like she’s doing what’s best for her,” Mikulak said. “It’s awesome to see that she’s gotten to go against the pressure of society and do what’s best for herself.”

The 24-year-old came to Tokyo as possibly the face of the Games following the retirement of swimmer Michael Phelps and sprinter Usain Bolt. She topped qualifying on Sunday despite piling up mandatory deductions on vault, floor and beam following shaky dismounts.

She posted on social media on Monday that she felt the weight of the world on her shoulders. The weight became too heavy after vaulting during team finals. She lost herself in mid-air and completed 1 1/2 twists instead of 2 1/2. She consulted with U.S. team doctor Marcia Faustin before walking off the field of play.

When she returned, she took off her bar grips, hugged teammates Sunisa Lee, Grace McCallum and Jordan Chiles and turned into the team's head cheerleader as the U.S. claimed silver behind the Russian Olympic Committee.

“Once I came out here (to compete), I was like, ‘No mental is, not there so I just need to let the girls do it and focus on myself,’" Biles said following the medal ceremony.

The decision opens the door wide open for the all-around, a title that was long considered a foregone conclusion. Rebeca Andrade of Brazil finished second to Biles during qualifying, followed by Lee and Russians Angelina Melnikova and Vladislava Urazova. The four were separated by three-tenths of a point on Sunday.

Carey now finds herself in the final, capping a remarkable journey for the 21-year-old from Phoenix. She spent two years traveling the globe in an effort to pile up enough points on the World Cup circuit to earn an individual nominative spot, meaning she would be in the Olympics but technically not be part of the four-woman U.S. team.

Carey posted the second-best score on vault and the third-best on floor during qualifying, earning trips to the event finals in the process. Now she finds herself competing for an all-around medal while replacing the athlete considered the greatest of all-time in the sport.