A rush of memories and emotions came back to three-time gold medalist Aly Raisman as she watched her former teammate from the 2016 U.S. women's gymnastics team, Simone Biles, compete in and ultimately withdraw from Tuesday's team final.

"It is so much pressure," Raisman said in an interview with ESPN. "It's the most pressure I've ever seen on a gymnast and maybe even Olympic athlete, and I can't imagine how hard it is for her.

"I'm very proud of Simone, and I can't imagine the bravery that it takes to just say, 'I'm not going to do it today.'"

After the U.S. women posted lower-than-expected scores in the qualifiers Monday, trailing the Russian Olympic Committee, Raisman posted a tweet that went viral that same night:

"I just wanted to remind people qualifying second place in the whole entire world is absolutely amazing and so much to be proud of," she said. "I just think sometimes people forget that Olympic athletes are human, and the mental health of athletes really matters. It's something that we need to continue to talk about and make sure that as a society we're all doing everything we can to support them."

Raisman was captain of the 2012 "Fierce Five" and the 2016 "Final Five," both teams that won gold at the summer games. Biles is the captain of this year's team, and Raisman questioned whether USA Gymnastics had adequate resources on hand to support Biles in Tokyo.

"When I was training, there really weren't resources for us to talk about our mental health or even ways to understand it," Raisman said. "So I'm not even sure if there is resources out there in Tokyo for Simone. ... We need to be asking the organizations like USA Gymnastics and the United States Olympic Committee: What are you doing to support your athletes and how can we prevent athletes feeling like they are struggling so much that they can't finish the competition? What can we learn from this? And how can we better support athletes?"

In a statement, U.S. Olympic & Paralymic Committee CEO Sarah Hirshland said: "Simone, you've made us so proud. Proud of who you are as a person, teammate and athlete. We applaud your decision to prioritize your mental wellness over all else and offer you the full support and resources of our Team USA community as you navigate the journey ahead."

Even if Biles doesn't compete in any more Olympic events -- although Raisman said she's hopeful -- what she did Monday will endure, Raisman said.

"She's still the most incredible gymnast," Raisman said. "And I think she's showing us and leading by example that prioritizing your mental health is crucial and it's really important."