The star running back was in-and-out of the hospital and was back on the field Tuesday resuming rehab work on his surgically repaired left knee.
Peterson's reaction came from jambalaya served in the team's training camp cafeteria. He experienced shortness of breath and swelling in his face. The Vikings' trainer stuck him with an "EPI" pen to improve his breathing, before sending him to the hospital.
"Like 20 minutes after I ate, I went to lay down and felt my throat itching and my ears itching and all of a sudden my face swelled up," he said Tuesday, via The Associated Press. "I couldn't breathe out of my nose."
Peterson is awaiting blood tests to determine the allergy. He said he eats jambalaya with seafood often and can't understand why his body reacted the way it did.
One crisis averted, Peterson now continues his quest to be cleared for practice with teammates.
"I definitely want to play a preseason game, and that's the only way to get back to normal," Peterson said. "Going out there and ... cutting and dodging guys and playing football. Getting back out on the field. Hopefully I will get the opportunity to do that."