Manning appeared on the "Late Show with David Letterman" on Monday and discussed the effects of having spinal fusion surgery, which caused him to miss the entire 2011 season.
"I'm not at 100 percent compared to what I was before my surgery. But I have made strides each season," Manning said. "And this year felt a lot better than I did the year before. These nerves just go at their own pace. It's not like it's going to have this immediate recovery one day. I had a lot of people who had nerve damage and told me any day you wake up and that's going to be the day."
Manning threw for an NFL record 5,477 passing yards and 55 touchdowns last season, winning his fifth NFL Most Valuable Player award.
"You talk about waking up excited every morning at 7 am and then being depressed at noon … because today's not the day," Manning said.
https://www.youtube.com/watch?v=cRK5ifu5zQ0 PHOTOS: Rare Photos of Peyton Manning