“I went to the doctor and, unfortunately, he told me I’m out of the competition,” she said on the program, according to the New York Daily News.
“Thank you guys for all the support! Means so much. Love you guys,” she tweeted after making her announcement on the show.
Webb, who was Miss Alabama USA 2012, sustained a back injury.
“I’ve had the worst time training this week because even the most simplest dives shot pain all the way from the middle of my back down my leg,” she said, according to Yahoo News. “I went to the doctor and unfortunately he told me I’m out for the competition”
Webb was replaced by comedian Louie Anderson.
“Ive really gotten to know @_Katherinewebb over the weeks we practiced together. She put all that she could into this,” Anderson tweeted.
Webb was the second celebrity to pull out of the show after Kendra Wilkinson left due to a fear of heights.