Fantasy Theory: Receiver Peak Age

At what age do receivers start to decline? Can you still safely draft WRs of 30 and older?

I think WRs start declining at age 28, on average. 

This is based on 1500 "seasons" for receivers since 2000. I collected their data, put everything in an excel sheet and crunched some data. I found 400 receivers with multiple seasons in the data, and base my numbers on this. I looked at the peak of their numbers, but also at the yearly increase/decrease. Eg Antonio Brown had his "peak age" at age 27 (1800 yards); the season after is marked as "decrease" (1293) but the season after that he improved again (1533 at age 29). I took all these peaks and all these percentage increases, and sliced and diced them in a number of ways. 

The chart above is a result of that. The line is the number of receivers for each age group. The numbers are highest around 25, because receivers that start to decline after that age, are generally dumped unceremoniously. If you're 24 you can get another chance after a couple bad seasons, but at 28, that's rare (and of course, career ending injuries are a factor.

The bars are the number of receivers that improved or decreased their yardage (or stayed within +/- 10%) compared to the previous season. The numbers don't add up to the full total for the same age group, because players sometimes miss a season, or dip so far below that they don't appear in the data.

So now, you can see that at age 32, the yellow bar (decrease) is clearly larger than the green bar (improved). For other age groups it's not that clear, so let's take the same data in a slightly different graph:

Now it's easier to compare the green (improve) and yellow (decrease) bars. 

- Until age 25 the green bar is clearly larger, so we can say that 25-yo receivers generally improve over their age 24 season

- after age 28 the yellow bar is consistently larger than the green bar, so 28-yo receivers generally decrease.

I've done this a number of times, with different groups of data, and each time I reached similar conclusions. WRs decline on average WELL before their 30th birthday. Yes, the best can stay on a high level for a long time, but that's not the argument. If you say "the decline for WRs doesn’t really hit until age 32", I say "I think it's earlier".