I threw together the graph below because I’m always interested in the implications that age has on the NFL game. Last week I wrote that careers for coaches probably peak around 51 or 52, and that a Super Bowl coach is likely to be younger than the average NFL coach.
I figured I would use the same methodology as I did in the post on coaches and apply it to running backs. I looked at about 3,000 running back seasons going back to 1990, calculated a career yards per carry average for each back, and then looked at each year of age in terms of its relation to the back’s career average. I do it this way because if I just look at the average yards per carry for say 28 year old running backs, the results will be fraught with survivor bias. Basically, only good running backs stay in the league long enough to be a 28 year old running back. But since I don’t want to compare good 28 year old running backs against all 23 year old running backs, I have to do it this way.
In short, when a running back is 25 years old, he’s probably about as good as he’s going to be in terms of efficiency, or yards per carry. After 25, things tend to go downhill. First they go downhill rapidly, then things are only getting worse slowly as they reach 30. The red line is career average.
Even though it looks like the line is going back up around 30, you have to keep in mind that’s relative to the running back’s career average. They’ve already been in decline for a few years. By the time they reach 30, they’re getting worse, but at a slower rate.
What’s actionable from this graph? Don’t give out huge contracts to running backs who are passing 26. From 27-29, running backs are pretty much just getting worse.
The difficult thing for NFL teams is that they often have to pay players for what the player did in the previous season, even though aging most of the time ensures that the team isn’t getting the same player in the next year. I know this sucks for NFL running backs who take a beating and then are almost over the hill when it’s time to get paid. The only thing I can think of is to pay running backs by the yard gained. Then you won’t have situations like Arian Foster playing for $500k while Chris Johnson is playing for $8 million.