Michaels told HuffPost Live she was "stunned" to see Frederickson's weight loss.
"I thought she had lost too much weight," she said.
"We are allowed to speak with our contestants after they go home...but no one had told me, 'Hey, Rachel is very, very thin.' Bob and I had no idea. Nobody had told us, nobody had said anything to us, so yes, I was stunned," Michaels, said. "Obviously, I thought she had lost too much weight and I was immediately concerned and wondering how this happened, how no one had said something to me and how the checks and balances that have been put into place, in my opinion, this had fallen through those checks and balances."
2014: The Year in Music [PHOTOS]