Bruce Arians said his overnight hospital stay was due to diverticulitis, an existing condition that flared up before practice on Tuesday.
Arians, 63, said late Wednesday morning that he's feeling "much better" and that he plans on attending Arizona's practice with the San Diego Chargers later in the afternoon.
"I'm too old not to listen to doctors anymore," Arians said. "I have a tendency to push it but I'll go out today and see how long we'll stay. It's nothing serious."
Arians has been on a fairly strict diet recently, which made Tuesday's health scare a surprise to the coach.
"It was odd that it happened," Arians said.