Simone Biles to 'probably' compete on beam, reveals Olympic teammate MyKayla Skinner

American gymnast MyKayla Skinner revealed her superstar teammate Simone Biles will "probably" compete on the beam in what would be her last chance at the Tokyo Olympic Games.

Biles dramatically pulled out of the team final last week, saying she was suffering from the "twisties", where gymnasts lose the ability to orient themselves in mid-air. She has since withdrawn from the all-around, floor, vault and uneven bar events to protect her mental health.

Biles' decision to skip the vault competition allowed Skinner to take her spot and scoop a silver on Sunday.

And the US gymnast said she believed the Tokyo Olympics wasn't over yet for Biles, who has openly talked about her struggles with her mental health during the Games.

"She's still probably going to be competing. I don't know for sure, it's kind of up to her," Skinner said, but added "yeah I think so", when asked whether the four-time Olympic champion would appear on the beam on Tuesday.

Skinner said Biles was "one strong cookie" but that the situation "has definitely hit her really hard".

"She's handling it better than I thought. Every day she's been laughing, giggling, super supportive," she said.

Biles was in the Ariake Gymnastics Centre on Sunday, cheering on her US teammates competing in the individual events.

USA Gymnastics said earlier in the day that a decision on her beam participation would come "later this week".

Biles, who is widely considered to have pushed gymnastics to new limits, came to Tokyo seeking five gold medals to equal the Olympic all-time gymnastics career record of nine.

But on withdrawing from the team final she said she wanted to "focus on my mental health and not jeopardise my health and my wellbeing".

Skinner said she believed Biles was "trying to stay in the game" to be able to compete again.

"I'm sure when she gets home it'll probably hit her more," she said. But, she said, Biles is "very mentally and physically tough".

"Whatever happens, I think she's just going to let it roll off and just continue with life, being the amazing Simone that she is."