The research conducted for this article will show the aging curve for NFL offensive players and offer a narrative for the results that were found. Specifically, what follows is a look at the aging curve for each offensive position in the NFL.
In my last post I detailed the methodology, value metric, and population that is used for this project, and you can read about it here.
To these three points, for people that don’t want to go back to the last article, (Methodology) this research employs the delta method, which minimizes the survivorship bias inherent in attempts at aging curves (i.e. we look at the actual change in player performance) and allows us to come up with the most robust look at NFL player evolution to date.
(Value Metric) Our proxy for a value metric is Pro Football Reference’s approximate value (AV) metric that looks to “put a single number on the seasonal value of a player at any position from any year (since 1950).”
(Population) To accommodate for the fact that players of this general era most likely do not age in the same way that players of the 60’s and 70’s aged, we will only include players from 1980 to 2014 in our population.
Again, you can find a complete explanation of all three points in the previous post.
Aging Curve for NFL Offensive Players
This graph was shown in the last article, but I thought that I would include it again so that all of the information for offensive players can live in one place.
Tackles seem to make their biggest leaps in development within their first three seasons, but once they reach their age 25 season, tackles see a steady rise to their peak season at age 28 and then age gradually until their age 31 season.
The peak period for a tackle appears to be from their age 25 to age 31 season with very little variation, except for the rise and fall to and from their peak, in performance throughout this time period.
Throughout this article we will judge the peak range or period of performance for each position as the number of years that fall within half an AV of a position’s peak season.
The most notable difference in the development between tackles and centers seems to be that centers are farther from their peaks when they enter the league than tackles.
Outside of the early part of their careers, centers appear to evolve in a way not too dissimilar from tackles. Centers and tackles both peak at 28, and while tackles start their peak period of performance at 25, centers begin their peak period at 26; also, both centers and tackles start their decline around the same period of time at 32 and 31 respectively, but, once they start their more rapid decline, centers fall farther from their peak than tackles. Said another way, centers seem to fall off considerably after their age 32 season when turn 33.
Guards and centers mirror each other when it comes to their pre-peak development, but guards seem to peak slightly earlier—at 27—than centers.
While we can see that guards decline slightly more than either centers or tackles after their peaks, it is also important to note that the peak period of performance for guards—four years from their age 26 to age 29 season—is shorter than the time centers and tackles are at their relative peaks—five years from their age 26 to age 30 season for centers, and seven years from their age 25 to age 31 season for tackles.
Quarterbacks are almost at their peak at 27, but are at their highest level of performance at 28. You can also see that quarterbacks develop the most within their first four seasons, and are near the version of best player that they will ever be in their age 25 season. The peak period of quarterback performance seems to be from 26 to 30—five seasons.
After a quarterback slowly declines from their peak, they take their first significant hit in performance at 31 and their second noteworthy drop in performance at 34.
For players that enter the league as 21-year-olds, this graph seems to confirm the public discourse around the third year breakout for wide receivers (i.e. the jump that receivers take from their age 22 to 23 season is the biggest jump that they take in their careers); for players that enter the NFL as 22 year olds, this is their second season.
Wide receivers seem to have a relatively short peak range of three years from 25 to 27, with their peak being their age 26 season.
From the time they enter the league at 22, tight ends improve rapidly until they reach their peak at 25. Once they reach their peak, they drop gradually until they turn 30; at 30, it appears that tight ends start a quick decline.
For a peak that lasts a total of three years, the peak period for tight ends starts in their age 25 season and lasts until their age 27 season.
Running backs that come into the NFL at 22 are closer to their peak than any other position, and, like tight ends, make large leaps in improvement until they reach their peak—24 and 25 (while 24 is the peak age for running backs, their age 25 season is nearly the same as far as performance).
For a total of four seasons, the peak range of performance for running backs proves to be from a player’s age 24 season to their age 27 season. Once they turn 28, running backs see their performance start to suffer.
While this graph is somewhat difficult to read, there are a lot of valuable insights to glean from it when comes to the comparison of the overall development and decline of players across each specific offensive position.
We can see, as a generalization, that the players that are the farthest away from their peak when they enter the NFL—quarterbacks, centers, guards, and tackles—ultimately age better than the positions that are the closest to their peaks when they enter the NFL—running backs, tight ends, and wide receivers.
From the chart above, we can see that there are two subsets of positions that cluster around certain ages for peak performance: what I call speed dependent positions and speed independent positions.
Tackles, centers, quarterbacks and guards fall into the speed independent group, and wide receivers, tight ends, and running backs make up the speed dependent group; the speed dependent group relies on their speed for success and the speed independent group doesn’t rely on speed as much (in this sense, speed independent is somewhat of a misnomer, because these positions still rely on their speed; they just don’t rely on it as much as the other positions do).
By the nature of these positions, the speed dependent group clearly relies on their speed and athleticism more than the speed independent group, and this dependence can generate a narrative for why the former group peaks earlier than the later group. If you operate from the assumption that players are the fastest, or close to as fast, as they will ever be when they first enter the league, it makes sense that they would peak early and decline as they lose their speed (this assumption is generated by the author from research done on the peak age of track and field athletes (no idea if this research used the delta method; the peak age could be different if a better methodology can be used); one could think that the speed dependent positions could peak slightly earlier in performance than track and field athletes because of the large amount of collisions that football players and their bodies have encountered over the course of their careers).
For the speed independent group, these players rely less on their speed and, with the exception of quarterbacks, are more reliant on their strength; offensive lineman seem to be at the perfect equilibrium of strength and speed around their age 28 season.
There are many implications for this work, specifically as it relates to roster construction and the investment in speed dependent players with long-term, expensive contracts. Wide receivers, tight ends, and running backs that enter the league as 22-year-olds are almost past their peak by the time they reach free agency for the first time (first round picks are locked into their rookie deals for four or five years, while all other draft picks are tied to their rookie contracts for four years), while tackles centers, quarterbacks, and guards have yet to play their best football when they are first time free agents.
The general rule for the aging curve for NFL offensive players is that speed dependent players peak earlier than speed independent players, but speed independent players age better than speed dependent players. Follow me on twitter to ask any questions about the project (or ask them in the comments section below) and find out when the aging curves for specific defensive positions have been released; this should happen within the next couple of weeks.
Photo Credit: Mike Morbeck
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