Players toil through pains great and small on the football field. They rarely want to talk about them.
"That was my least favorite play, because running to the outside, my whole right side was exposed," Williams told The Arizona Republic on Thursday. "As soon as I saw (linebacker Brandon) Spikes coming to hit me, I curled up and forgot about the ball. It was something where I was trying to protect my leg instead of trying to protect the football.
"It's a scary sight being a running back and being scared to run the ball. That's something that no running back should feel. I was pretty much scared all last year to get the ball in my hands."
Williams called his season-ending shoulder injury in October a "blessing in disguise" for the chance to shut it down and heal the knee. Williams says he's healthier than he has been in two years, but he's now in a fight for his job after the Cardinals signed Rashard Mendenhall, an old favorite of new coach Bruce Arians.
We haven't seen what a truly healthy Williams is capable of. Perhaps we'll find out this season, but the more pressing question is this: Why did he even step on the field last season?
Follow Marc Sessler on Twitter @MarcSesslerNFL.