I’ve done a lot of research on NFL rookies because, with so many unknowns coming into the league, I think they typically represent a good opportunity to exploit a marketplace inefficiency. That doesn’t mean always being bullish on first-year players; in general, I think rookie runners and mobile quarterbacks are undervalued, while pass-catchers typically get over-drafted.
There are lots of factors other than position that go into projecting each rookie; his draft slot is incredibly important, as is size, speed, offensive system, anticipated workload, and so on. But what about age? I’ve completed a lot of work on fantasy production by age, but that analysis hasn’t separated rookies from the rest of the pack. How does a 24-year old rookie quarterback compare to a 21-year old?
Basically, what I’m doing here is trying to isolate age from NFL experience. We know 23-year old wide receivers perform better than 21-year olds, for example, but is it because of the actual age difference or just because they’re typically in the league longer? We should be able to determine that by analyzing only rookies at different ages.
I researched the production of every rookie since 1995 to start at least 10 games. I included only true rookies, not players like Aaron Rodgers who sat on the bench for a few years before taking over as the starter. Here’s what I found.
If there’s a position where you’d think NFL experience would matter most, it’s quarterback. But age and maturity also seem to matter, regardless of experience in the league. First, take a look at how rookie quarterbacks have fared in terms of passing yards at ages 21 through 24.
Rookies ages 22 through 24 have produced at right around the same level in terms of bulk yards, while the youngest first-year quarterbacks—including Matthew Stafford and Josh Freeman—struggled more in their first seasons.
Age’s effect on touchdown-to-interception ratio is even more pronounced.
That’s pretty good evidence that older rookies outperform younger ones at the quarterback position. Presumably, their college experience and maturity helps them produce at a higher level right out of the gate in the NFL.
The average 24-year old rookie to start 10 games has thrown nearly 14 touchdowns to 11 picks; that ratio is closer to 11 touchdowns to 19 interceptions for 21-year olds. In terms of passing yards, touchdowns, and interceptions alone, the typical 24-year old rookie passer can be expected to score 46 more fantasy points than a 21-year old.
Since I’ve shown that running backs record their highest fantasy points per touch basically from the moment they enter the league, it’s not surprising that rookies who start 10-plus games—and thus receive a heavy workload—produce best as at young ages.
Unlike quarterbacks, NFL experience probably doesn’t matter all that much for running backs in terms of fantasy production. You’d probably find that 32 out of 32 NFL head coaches disagree about the importance of experience for running backs because they need them to do things like learn pass protection schemes. That’s important for all of you who are in fantasy leagues that award points for effective blitz pickup. For the rest of us, we can go ahead and just worry about catches, yards, and touchdowns.
To display just how much superior young rookie running backs are to older rookies, I collected a shitload of data on a couple hundred of them. Take a look. First, rushing yards…
Um, think there’s something there? Twenty-one year-old rookie running backs have posted the best numbers in every meaningful statistical category, sometimes by a wide margin. The average 21-year old rookie back has rushed for nearly 4.50 YPC, while no other age group has checked in above 4.25 YPC.
There are probably some other factors working here that I’ll discuss in a bit, but you’d think that at least part of the explanation for these numbers is that running backs are an anti-wine, getting worse with age.
We know that wide receivers take time to develop in the NFL; we typically see a huge jump in fantasy production for wide receivers in their second and third years in the league. But how much of that improvement is due to experience in the league and how much is just because the players are getting older and maturing? Again, to solve that puzzle, we can look at rookie production by age.
Very interestingly, young rookie wide receivers have outplayed older ones. The typical 21-year old rookie receiver—a group that includes Randy Moss and Larry Fitzgerald—has posted over 23 percent more receiving yards than the average 24-year old rookie.
We see the same effect with touchdowns…
For all three stats, the difference between the 21-year old group and the 24-year olds is an improvement of between 17 and 29 percent. Thus, the typical 21-year old rookie wide receiver is probably going to give you somewhere in the neighborhood of 25 percent more fantasy points than rookies who are three years older.
Before I interpret this data further, let’s take a look at the tight ends.
Tight ends frequently produce efficiency metrics that resemble those of big wide receivers—a relatively low yards-per-reception and a very high red zone touchdown rate. Thus, we often see tight end fantasy numbers resemble those for wide receivers. That’s true for rookies.
There’s a jump in production for 24-year old rookie tight ends—a group that includes John Carlson and Dustin Keller—but we still see 21-year old rookie pass-catchers putting up the most yards.
The same goes for touchdowns, but not receptions.
I’m not entirely sure why there’s a deviation between the numbers for 24-year old rookie wide receivers and first-year tight ends of the same age, but there’s still a general downward trend at the tight end position. Twenty-one year-old rookie tight ends post more yards and touchdowns than rookies of any other age, and the second-best number of receptions.
Why Young Rookies Excel
The youngest rookies thrive at every position other than quarterback, probably since maturity and experience—in college or the NFL—matter a lot for passers. But why the steep drops for older rookies at the other positions?
When combined with the data on fantasy production by age (for all players, not just rookies), the numbers in this study seem to suggest that experience doesn’t matter much for running backs, but it does for pass-catchers. Running backs record their best efficiency from a young age, and they seem to maintain that success regardless of their NFL experience. Thus, age really does seem to matter for backs.
I thought the same was true of pass-catchers—I believed 24-year olds were naturally better than 21-year olds because of physical maturity—but now I’m not sure that’s the case. It seems like 24-year old receivers (of any NFL experience level) normally have better numbers than 21-year olds, for example, because they’re in the NFL for a longer time, not because of the age itself.
If young wide receivers improved because of age, we’d expect that older rookies would outperform younger ones. We don’t see that, though, suggesting pass-catchers, like running backs, are naturally near their peak (in terms of physical ability) at a young age. The pass-catchers become more efficient in the NFL with experience, though, while running backs don’t.
When you think about the nature of the positions, too, this idea makes sense. Quarterbacks obviously need time to learn the playbook and figure out how to decipher defenses far more complex than those in college. Pass-catchers need time to learn little nuances of route-running and to develop chemistry with their quarterback. Wide receiver and tight end play is less about pure athleticism—especially in today’s NFL with size trumping speed at those positions—and more about playing intelligently, sitting down in zones, figuring out how to get a clean release off of the line, and so on.
Meanwhile, I’ve shown that running back production is dependent on offensive line play and pure explosiveness. Pass protection might improve with more NFL experience, but the same doesn’t appear to be true for a running back’s stats.
Finally, I want to mention that I think part of the effect is due to younger rookies perhaps being superior players in general. When a young college player declares himself eligible for the NFL draft, there’s a good chance that he believes his draft stock is at or near its peak. Thus, we might expect 20 and 21-year old rookies to just be better players than older rookies who enter the draft only because they don’t have any more seasons of college eligibility.