There's a lot of really strong dynasty analysis out there, especially when compared to five or ten years ago. But most of it is so dang practical-- Player X is undervalued, Player Y's workload is troubling, the market at this position is irrational, and take this specific action to win your league. Dynasty, in Theory is meant as a corrective, offering insights and takeaways into the strategic and structural nature of the game that might not lead to an immediate benefit but which should help us become better players over time.
A "What" Without A "Why"
For most fantasy football content, the "what" tends to be the headline, and the "why" (if it's offered) largely exists in support. When I write about streaming kickers, people read (or not) because they want to know what kickers to start this week (or don't); I'll explain why my model likes who it likes, but I know that's not why everyone is clicking through.
One of my favorite parts of writing a less practical column like this is I get to invert the formula, treating the "what" as the afterthought-- it exists solely as a jumping-off point, an excuse to diagnose the various whys and discuss them at length.
I've been meaning to write up this week's topic for a while now, but I've always come up short because, while I'm super-clear on the "what", I have no idea on the "why" that's driving it. And without knowing the "why" it's hard to offer actionable advice.
But ultimately, the "what" is pretty important-- perhaps the single most important fact to monitor and be aware of in dynasty right now-- so I feel compelled to write about it anyway. I'm not entirely sure why it's happening, but I'm pretty sure NFL careers are getting shorter.
Examining the Evidence
For a long time, it was taken as an article of faith that advancements in training, nutrition, and medical science (as well as an increased focus on player health and safety) would extend careers. And a few high-profile outliers likely convinced many that that was taking place. Tom Brady won an MVP at age 40 and was a second-team All-Pro at 44. Travis Kelce is likely to make his ninth straight Pro Bowl at age 34 and is a good bet to earn his fifth first-team All-Pro while he's at it. Adrian Peterson had 1200 scrimmage yards at 33, 1000 scrimmage yards at 34, and even recorded a 100-yard effort in his first game with a new team at age 35. Frank Gore started 14 games at 37.
But outliers have always existed. Marcus Allen logged 1100 scrimmage yards at age 35 and 36 back in the '90s. John Riggins logged 380 touches and was a first-team All Pro at age 34 in the '80s. Joe Perry was a regular starter to age 35 back in the '60s. Y.A. Tittle won an MVP at age 37 back in 1963. Don Maynard, Charlie Joiner, and Jerry Rice set standards for longevity in the '70s, '80s, '90s, and '00s.
The best way to track longevity is not through the single oldest player at a given position but through the prevalence of old players in general. And on that count, the last decade has been one of the worst in history.
Here's the number of 1,000-yard seasons by a player who was age 30 or older by December 31st of that year:
1993: 3
1994: 4
1995: 9
1996: 8
1997: 6
1998: 7
1999: 7
2000: 6
2001: 10
2002: 7
2003: 3
2004: 10
2005: 8
2006: 7
2007: 10
2008: 6
2009: 7
2010: 2
2011: 3
2012: 6
2013: 3
2014: 3
2015: 6
2016: 7
2017: 1
2018: 1
2019: 3
2020: 1
2021: 1
2022: 3
There's a lot of noise there, so let's aggregate that into six-year buckets:
1993-1998: 37
1999-2004: 43
2005-2010: 40
2011-2016: 28
2017-2022: 10
This comes against a backdrop where more and more players are reaching 1,000 receiving yards in any given year. In 1993, just nine players topped 1,000 yards and 3 of them were 30 or older. (Three more were 28, two were 27, and one was 26.) 2022 saw the same number of 1,000-yard receivers who were 30 or older despite 22 different players reaching the mark overall. Here are the buckets again in terms of what percentage of 1,000-yard receivers were 30 or older:
1993-1998: 33.0%
1999-2004: 33.3%
2005-2010: 33.1%
2011-2016: 20.4%
2017-2022: 7.7%
Now, to be fair, old receivers are having a bit of a resurgence this year: Travis Kelce, Adam Thielen, Davante Adams, Keenan Allen, DeAndre Hopkins, Stefon Diggs, Mike Evans, and George Kittle all have at least 700 yards, which puts them on pace for 1,000. They represent 25% of all players with at least 700 receiving yards, which would be quite the rebound, though still wouldn't get us to pre-2011 levels.
Either way, this isn't just the pattern at wide receiver. Here's the number and percentage of 1,000-yard rushing seasons by a player age 27 or older:
1993-1998: 27 (31.4%)
1999-2004: 48 (45.7%)
2005-2010: 44 (42.3%)
2011-2016: 33 (43.4%)
2017-2022: 10 (15.2%)
120-tackle seasons by a player 30 or older:
1993-1998: 25 (26.9%)
1999-2004: 17 (17.7%)
2005-2010: 25 (27.5%)
2011-2016: 19 (20.7%)
2017-2022: 11 (9.7%)
Here's the number of times an offensive lineman started 14+ games at age 34 or older:
1993-1998: 54
1999-2004: 45
2005-2010: 43
2011-2016: 27
2017-2020: 24
(I'm not including a percentage because, unlike the number of rushing or receiving yards or tackles, the number of starts remains roughly constant from season to season-- with the only variation owing to league expansion in 1995, 1999, and 2002, and the move to 17-game seasons in 2021.)
Not every position shows the same pattern. Here's the number of 10+ sack seasons by a player 30 or older, for instance:
1993-1998: 45 (39.1%)
1999-2004: 18 (17.5%)
2005-2010: 23 (24.0%)
2011-2016: 31 (27.7%)
2017-2022: 22 (21.2%)
But enough positions show a significant decline, and those declines largely coincide, which leads me to believe there's a real effect at play here.
What Might Be Causing This?
There are a lot of possible culprits, but none seem to line up perfectly or explain everything. When I first noticed the pattern, I assumed the problem was the Collective Bargaining Agreement signed before the 2011 season. That CBA dramatically changed rookie compensation, capping their salaries, barring them from renegotiating or signing an extension in their first three years, and giving teams a 5th-year option to add an extra cost-controlled season for all first-round picks.
At the time, it was thought that capping earnings for players who weren't yet in the NFL would leave more money going to veteran players. And since the NFL has a salary floor, that's technically true-- any savings on rookies must be passed on to veterans. But those savings aren't distributed evenly; because rookies were suddenly so cheap, teams stocked the end of their roster with them, replacing the long-term veteran minimum players who once populated that region. A 7-year veteran in 2023 is guaranteed at least $1.65 million a year; by contrast, a late-round rookie only makes $750k.
In the '90s and '00s, teams used to frequently have players like Keith Burns of the Denver Broncos. Burns was drafted as a linebacker in the 7th round of the 1994 NFL draft. He never made it on defense, starting just three games in his career, but he was a special teams standout, appearing in 197 games and logging 187 tackles-- bringing down an average of nearly one returner a game for thirteen years. Plenty of other franchises have their own Keith Burns-- Larry Izzo with the Dolphins and Patriots, Steve Tasker with the Bills, etc. Today, it's a dying breed.
Those cash savings from cost-controlled rookie contracts have instead flown to a shrinking pool of stars. Quarterback salaries keep rising. The wide receiver market was recently obliterated and completely reset. A few players find themselves dramatically better off; most find themselves replaced by cheaper alternatives.
At least, that's a compelling story to explain the decline. But as I said, it doesn't quite line up with observations. For one thing, the timing isn't quite right. The truly dramatic drop in productive veterans didn't happen until around 2017, six years after the CBA was signed.
Did teams just take a while to figure out the new reality? Perhaps, but there's a bigger problem: if the veteran attrition is largely happening at the end of the roster, it should manifest in a decline in 300-yard seasons or 500-yard seasons among players 30 or older. 1,000-yard receivers are the stars of the NFL, guys like Mike Evans and Keenan Allen-- guys who are presumably the winners in the new CBA.
Are there other explanations that fit? A few, sort of. But none very well.
My go-to explanation when there are shifts in typical player ages is that they're probably the result of fluctuations in incoming talent. If a lot of phenomenal quarterbacks enter the league in a six-year span (as was the case from 2000-2005 with Tom Brady, Drew Brees, Philip Rivers, Eli Manning, Ben Roethlisberger, and Aaron Rodgers), you're probably going to see a lot of productive old quarterbacks fifteen years later (as was the case with... you know, those guys).
But that explains why some positions fluctuate. Wide receivers got younger after 2014 because 2014 was a phenomenal class for wide receivers... but running backs kept getting older until 2017, which was a phenomenal class for running backs. We shouldn't expect to see so many different positions moving in the same direction at the same time if it's just random variation. That calls for some sort of structural explanation.
There are some compelling structural explanations available. Perhaps as the college game evolves it produces players who are more immediately ready for the NFL, and those pro-ready players start displacing the older stalwarts quicker than they used to. Or perhaps when the league as a whole was less athletic, it was easier for an aging player to keep pace as his athleticism declined, but as it gets bigger and faster and more competitive, it becomes harder for older players to remain relevant.
These structural explanations come with their own problems-- the biggest of which is: why would this manifest suddenly instead of gradually over a long period of time?
Maybe it's all random fluctuations after all-- similar patterns at different positions makes this explanation less likely, but not impossible. Maybe several of these explanations are all contributing a little bit. Maybe it's something I haven't even considered yet.
Why Does The "Why" Matter So Much?
In 2015, I wrote that we were probably thinking about age the wrong way in dynasty. The dominant method for modeling aging then (as now) was "age curves", where one averages production from players across all ages to determine when positions are typically ascending and when they are declining.
The problem with age curves is that NFL careers are rarely curve-shaped. (The curve arises in the aggregate because of something called the ecological fallacy, which states that relationships that are true at the population level are sometimes not true at the individual level.) Instead, I argued we should look at aging like mortality risk: everyone eventually "dies" (or, in this case, "falls out of fantasy relevance"), the chances of it happening increase with age and can be modeled probabilistically, but the outcomes themselves are binary. Either you're dead or you're alive. Either you're fantasy-relevant or you're not.
Using this paradigm, I created mortality tables that modeled a player's "death rate" by age and position based on historical data from 1985 to 2014. These tables do a great job of estimating how many prime years we should expect from a given player. At least, they do a great job as long as NFL aging patterns remain the same as they were from 1985-2014. Which they were... until sometime around 2017.
If I knew why NFL careers were getting shorter, it'd be easy to adjust for this. And more importantly, if the underlying facts driving the shift ever changed, we could adjust once again. If the problem was the CBA, then if the NFLPA bargained for a new CBA that removed the cap on rookie wages or allowed them to renegotiate contracts after a single season, we could move back to the old aging expectations. If the problem was rising athleticism, we could remain at the new aging expectations. If the problem was just random fluctuations over small samples, we could refrain from abandoning the old expectations in the first place.
It bugs me not knowing why something is happening (and if you have any theories, I'd love to hear them). But I'm pretty sure this is happening, and given its importance, I thought it was something everyone should be aware of. NFL careers seem to be getting shorter overall; we should probably make sure our dynasty values reflect that.