It turns out that the 217-pound running back is allergic to shellfish.
"I thought I was Superman until I experienced that life-changing anaphylactic shock,'' Peterson told USA Today in a new interview. "I was eating lunch and gobbled down a couple of bowls of gumbo."
"Then, 15 minutes later, I'm in my dorm room resting up. My eyes started itching and my throat was swelling up. I could barely breathe," the 28-year-old Texas native said.
Feeling his throat closing up, Peterson called Vikings trainer Eric Sugerman, who raced to his player's aid with an EpiPen until he could get to the hospital.
The allergy scare has inspired Peterson to partner with the maker of his EpiPen on an Anaphlaxis Preparedness Campaign.
For now, Peterson is still coming to terms with his allergy:
"Seafood was always my favorite food. I mean fried lobster? Come on."