Lewis told Buffalo Bills.com: "I'm going to tell you the worst part; I caught the stomach flu, so I was throwing up with my sore ribs. It was not cool. I couldn't sleep. I finally got a recliner sent to my room and slept on the recliner. Last week was really tough.
"One day last week I was like, 'Yeah I'm feeling better.' I was walking up to breakfast and I said, 'I'm going to take the stairs today.' A few steps up I sneezed and it brought me down to my knees. I changed my mind and took the elevator. Sneezing hurts!
"I'm an ultra-competitive person and I wanted come back bad and help my team out against the Chiefs, but I felt if I couldn't be myself I would be doing those guys an injustice. Going out there if I couldn't throw the ball the way I can throw it or run and protect myself. I just needed more time."
First-choice quarterback EJ Manuel is expected to be fit for Sunday's game with the Pittsburgh Steelers.