Christian Petersen/Getty Images

UFC champion called out by opponent after backing out of UFC 213 main event

The fight was called just hours ahead of the card starting.

It was a chaotic Saturday afternoon ahead of a UFC 213 card that was stacked from top to bottom. That was before Amanda Nunes' two hospital visits resulted in her bailing from her bantamweight title defense against Valentia Shevchenko.

About three hours before the card started, UFC president Dana White ruled Nunes (7-1) out of her bout with Shevchenko (3-1).

Here's what White said, via ESPN:

"Yesterday, she started to not feel good, so we took her to [the] hospital," White said early Saturday evening on SportsCenter. "[The doctor] did a full evaluation and she was medically cleared to fight. She weighed in at the ceremonial weigh-in [Friday] and squared off with Shevcheko, then went home last night.

"This morning, [Nunes] called again and said she didn't feel good. So they brought her back in [to the hospital] and started running tests on her, and she said she didn't want to fight ... she didn't feel good and didn't want to fight. She was medically cleared to fight, was checked and everything was fine, but she said she didn't feel right."

A frustrated Shevchenko later took to Instagram to call out Nunes:

"Today I am 100% ready for this fight. During the last 3 months of training I did everything to be in my best shape for this fight. Nunes couldn't cut weight correctly and was hospitalized. She wanted to cut weight and recover rapidly to have the advantage. The end result, everything went wrong. Even though she was medically cleared to fight, she backed out. This fight was originally offered to take place in April and she would not accept then. I did my part and am very upset that I can't fight for the title today on this great event. I am even more upset for all my dear fans who support me every time throughout the world and to those who traveled to see me fight here in Las Vegas live. I feel frustrated about what happened but I won't relax, will not put down energy in my preparation, and will wait until the UFC gives us another date for the fight. #UFC213 #teamBullet"

https://www.instagram.com/p/BWTiHSWAZmB/

The key here is doctors cleared her, twice apparently, to fight. It's obviously frustrating for Shevchenko on many levels, and even dominant strawweight fighter Joanna Jedrzejczyk was ready to step up and take the fight on short notice.

That obviously did not happen, leading to Yoel Romero's bout with Robert Whittaker being moved up to the main event for the interim middleweight crown.

White hopes to push Nunes-Shevchenko to early September in Edmonton.