Fred Jackson has said that he did not feel 100% fit at any point during the 2012 NFL season.
The Buffalo Bills running back missed the first game of the season with a knee sprain, was ruled out of one game with a concussion, and sustained another knee injury in December to keep him out of the final three games of the season.
Jackson told the Bills' website: "80% is a good number. That was probably the best I felt all year was 80% healthy.
"You have to go out there and play off emotion. Just like I needed to be a spark for them I had my teammates telling me they liked to see me back out there. Feeding off of that and playing off of that helped me get through it.
"I know it's going to be said that this guy is 32-years old when he comes into the season next year. Look at the season he had last year. Injury prone will probably be another label and that'll just be fuel for the fire. I love it."
Jackson rushed for 437 yards in the 10 games he was able to play in, scoring three touchdowns.