A deeper dive into linebacker aging as K.J. Wright and Bobby Wagner continue their greatness

Last week we looked at the distribution of players on NFL rosters from Week 1 of the 2018 season by age to get a high level look at what kind of aging curve the Seattle Seahawks might be looking at as they negotiate a third contract with All Pro linebacker Bobby Wagner.

There is no doubt that the age distribution for a specific position group will be distorted by survivorship bias, as younger players that may be on rosters early in their careers but fail to develop won’t stick around long. In addition, many special teams players may not make large contributions on defense, but might stick around in the league on a roster as primarily a special teamer for several years while never playing many meaningful snaps on the defensive side of the ball.

Thus, in order to get a better look at what an aging curve for Wagner might look like, I narrowed things down using the methodology of a commenter suggested in the original article. Specifically, what I did was I looked at all linebackers who started twelve or more games in their rookie season and then looked at the age at which each of these players last started ten or more games.

The data I looked at was players whose rookie season was between 1997 and 2009, a time period which allowed for a sample of 55 such linebackers. That is far from a huge sample, but it is large enough to begin to draw some basic understanding of the aging curve, while also representing players who are old enough that they are no longer active.

Of the 55 linebackers who entered the league during this time period, only three remain active, including Derrick Johnson, Brian Orakpo and Clay Matthews. Two of those three players are edge defenders as opposed to interior off ball linebackers like Wagner, but just keep those names in mind because as they are still in the league, they could theoretically continue to pull the aging curve to the right in Wagner’s favor (they are represented in the data as points at 32, 32 and 35).

Without too much more discussion, here is the data.

Now, I’m much more of a visual learner, and I’m sure many readers are as well, so here is that same data in chart form.

Now, that obviously shows that linebackers careers enter the danger zone at some point in their late twenties, and that while the odds of Wagner continuing to contribute for the Hawks remains high, they start to diminish rapidly over the coming seasons.

One topic of note specifically is that player aging is not a smooth and natural decline over time. Player aging in the NFL can be much more accurately looked at along the lines of a mortality distribution, as so many players are able to perform at a high level until all of a sudden a single injury forces them out of the game. Thus, looking at the preceding data from that standpoint, here is what the distribution of this data looks like when evaluated from a survivorship perspective.

What that chart shows us is that of linebackers that start at least twelve games during their rookie season, we can expect around eighty percent of them to start at least ten games in their age 28 season. Once those players get past their age 28 seasons, however, is when a rapid decline is often seen. Thus, Wagner having started fifteen games in his age 28 season has entered the period of his career where things could get derailed by a single play.

Obviously, that is not to say that he will be finished anytime soon, as full twenty percent of the players in the sample started double digit games in their age 33 season or later (this represents twenty-five percent of the players that made it to their age 28 season). That does, however, carry the implication that there is a three in four chance of Wagner not making it to his age 33 season. In fact, by the data in the sample, the odds of him starting ten or more games anytime in his age 31 season or older are roughly a coin flip.

This is important to keep in mind simply because Wagner is already under contract for his age 29 season, meaning that any extension would begin with his age 30 season. Thus, that age 31 season where his availability based on the data from the sample is worse than winning a coin flip is going to be the second year of any extension, and that is considering the fact that he started ten or more games in his age 28 season.

Now, I know some commenters are going to jump right to the comments and chime in that the data are not representative of Wagner because of the fact that he’s different because he’s a five time Pro Bowl, four time All Pro linebacker, but that is not going to make much of a difference. Yes, his skills and ability will be coming from a higher peak, so he will not likely be subject to a skill decline that prevents him from playing at a high level going forward, but the data is filled with samples of just such players.

For example, while he’s not in the data set, K.J. Wright is an example of how age can sneak up on a player in their late twenties. Between the time he was drafted in 2011 and 2017 Wright missed just five games over seven seasons, and then in 2018 missed eleven games due to a knee injury. Similar examples from high level players at different positions for the Seahawks can be seen in names like Kam Chancellor, Richard Sherman and Doug Baldwin.

Chancellor missed just ten games due to injury (this excludes the two games he missed in 2015 due to his holdout) over the first seven seasons of his career before a garbage time neck injury brought his career to a sudden halt at age 29. Sherman didn’t miss a snap over a more than ninety game streak covering parts of seven seasons until all of a sudden a single injury ended his time with the Hawks. Baldwin had missed just two games over his career, until a myriad of injuries caused him to miss three games in his age thirty season, and put his future in question following at least three offseason surgeries.

Looking specifically at the linebacker position, there are plenty of examples, including Al Wilson who was an All Pro linebacker for the Denver Broncos until a neck injury during his age 29 season brought his career to an abrupt halt. Jamie Sharper played every single game for the Houston Texans and Baltimore Ravens over a period of eight seasons, but a single injury eight games into his age 30 season ended his career. Patrick Willis was a seven time Pro Bowler and five time All Pro, until a toe issue caused him to miss ten games at age 29 and led him to hang up his cleats. In short, here’s the linebacker survivorship chart once a player has started at least ten games in their age 28 season.

In summary, Wagner is likely to continue to perform at a high level, but the odds of an injury bringing his career to a close are not insignificant. Thus, while the team has seen poor outcomes from third contracts it has handed out in the past, including to Chancellor and Marshawn Lynch, that doesn’t mean it should not work to extend Wagner. The team has the ability and opportunity to Wagner, but it should most certainly take advantage contract structures which carry less risk for the team than some of the contracts the front office has signed in the past.