By any measure, a season in which a running back gains over 1,300 yards from scrimmage and scores 14 touchdowns in 15 games should be considered a success.
"It was just frustrating," Charles said, per the Kansas City Star. "It wasn't the line; it was just me getting hurt. I had never played a whole season where I had nagging injuries and I can go in and I've got to come back out because my ankle hurt. And that was all the frustration? it wasn't about the team. The team did a great job. We won nine games last year, so it couldn't be the team."
Charles will turn 29 by the end of the 2015 season, an age when running backs are known to begin a steep decline. Charles has other plans.
"(The game) has changed," Charles said. "They've got all kinds of technology now, all kinds of medicine people have come up with to stay healthy. At the end of the day, an ACL you couldn't play (with), it was the end of a career. Now they've got all kinds of things that you can be back in like five or four months. The future is changing, football is changing, sports are just changing.
"You can see basketball, like Kobe Bryant, he is still playing at 36. You see Tim Duncan (is 39) ... I want to play another six years, so my form is to keep on taking my diet. I'm seeing guys at 37 or 38 still playing football in the trenches, and that's somewhere where you don't want to play."