Print

Running Back Age and Experience

You are viewing free content provided by FantasyGuru.com. Why not consider subscribing today?

by Mike Horn, Staff Writer

Published, 4/21/14

 

I was reading the latest Stock Watch when I came to the section on Maurice Jones-Drew. I have a great fondness for MJD, who I took in the 2nd round of my dynasty league’s rookie draft when he came into the NFL. He has been very good to me in that league and many others over the years. But as the Stock Watch points out, he is now 29 years old and is entering his 9th season in the league. Which of those factors is most important – age or time in the league (as it correlates to wear and tear) for predicting future performance? I’ve been writing about this question for a long time, and that link points to an article written just after MJD’s rookie year. I’m not going to exactly answer it here, but I have a couple of interesting observations.

 

I looked at all RBs since 1988 and their fantasy points per game (FPG) using standard (non- PPR) scoring (10 yards = 1 FP, TDs = 6 FP). For this study, I ignored the stray points that RBs pick up catching the ball.  “Age” is the season minus birth year, so a player born in 1980 was 26 in the 2006 season, regardless of whether he was born on 1 Jan or 31 Dec.

 

The first chart shows years of experience (seasons played) in the NFL on the horizontal axis and FPG on the vertical axis. Each curve represents the RBs of a certain age. I arbitrarily looked at only RBs in what I’d call “middle age” for the position, clearly no longer young backs but maybe not old either. (You could argue that 31 is old for an RB and I’d probably agree). I also started each curve at somewhat arbitrary points; you can find 27-year-old backs with just one or two years of playing time, but they are outliers.

 

 

 

There are exceptions, but generally here’s what I see in this chart:

 

·         For any amount of experience, younger RBs outscore older RBs.

·         For any age of RB, the more experienced RBs score more.

 

As an example of the first bullet, go across the x-axis to 8 years of experience and read up: first you hit the age 31 curve (black) at 4 FPG. Just above it (4.5 FPG) is the age 30 curve (green). Then you come to the age 29 curve (red) at 6.9 FPG. Finally, at the top is the youngest curve at this level of experience, the age 28 curve (blue, 12.5 FPG).

 

You can do this at any level of experience and with only a couple of exceptions, the younger RBs are better, as a group. So age is the key, right?

 

But then look at the second bullet. Take the age 29 curve (red). At four years of experience, those RBs averaged 2.9 FPG. At five years, they managed a little more, 3.6 FPG and then 3.8 at six seasons. After seven years, they were at 4.8 FPG, 6.9 at eight years, and a whopping 13.4 for the 29 year olds with nine years in the NFL. So experience is good, right?

 

I think not. I do think age is important, partly from what I said in my first bullet. But remember whether we read up from the x-axis or along each curve, we are comparing different groups of running backs at each point. Attrition of players due to underperformance or injury gradually reduces the number of RBs represented along each age curve and going up from each point on the x-axis, so that as the chart is read from left to right and bottom to top, each point represents a better group of players as selected by the relentless winnowing process of the NFL. This is a classic example of survivor bias in the data.

 

Go back to the age 29 curve (red). At nine years of experience, this is the highest point on the graph.  Why? In my opinion, RBs who are both good enough to be given a chance to play in the NFL at age 21 (that’s what 29 & 9 means – they had to start in the league at age 21 to get 9 years in by age 29) and still be playing at age 29 are a very good group of players, even if they are past their prime.

 

How good?  Here’s the players represented by that last red dot:

 

29&9

Jerome Bettis

Marshall Faulk

Ahman Green

Steven Jackson

Edgerrin James

Amp Lee

Clinton Portis

Barry Sanders

Emmitt Smith

 

Necessarily, the 30 & 10 dot is drawn from the same group but notice the attrition:

 

29&9

30&10

Jerome Bettis

Jerome Bettis

Marshall Faulk

Marshall Faulk

Ahman Green

Ahman Green

Steven Jackson

Steven Jackson

Edgerrin James

Edgerrin James

Amp Lee

 

Clinton Portis

 

Barry Sanders

Barry Sanders

Emmitt Smith

Emmitt Smith

 

The two worst performing players at age 29 dropped out and while the final dot on the age 30 curve (green, 30 & 10) is lower than the 29 & 9 dot, it would be a lot worse if Portis and Lee counted against it too.

 

Back up to the final dot on the blue curve (28 & 8).  Here are those players:

 

28&8

29&9

30&10

Jerome Bettis

Jerome Bettis

Jerome Bettis

Marshall Faulk

Marshall Faulk

Marshall Faulk

Ahman Green

Ahman Green

Ahman Green

Steven Jackson

Steven Jackson

Steven Jackson

Edgerrin James

Edgerrin James

Edgerrin James

Amp Lee

Amp Lee

 

Clinton Portis

Clinton Portis

 

Barry Sanders

Barry Sanders

Barry Sanders

Emmitt Smith

Emmitt Smith

Emmitt Smith

Robert Smith

 

 

Rodney Hampton

 

 

Reggie Bush

   

Maurice Jones-Drew

   

 

Again, you can see the attrition. Also, we have a MJD sighting. He and Reggie Bush have not yet played their 29 and 9 season. But the fact that they apparently will, along with the group of RBs they will be joining, says something about how good they have been.

 

The next graph adds a curve for the 29 and 9 cohort in the table above (minus Amp Lee who clearly is not at the level of the other backs – through age 28, he averaged 5.2 FPG for his career, the rest of this group had a career average of 14.9 at this age).

 

 

 

The 29&9 players top out at six years of experience or at age 26. From then on, they are in almost constant decline as a group. There was a slight uptick at age 29 because Barry Sanders had the best year of his career at that age. Without him, the group averaged 12.6, which would smooth the curve very nicely.

 

Here’s MJD, Bush, and the 29&9 (minus Amp Lee) cohort compared, including all of the first nine seasons:

 

 

 

MJD’s career up to year six is a decent match for this curve. Only in his 2nd season was he well below average and in two seasons he was above the average for a very good group of players. In the last two years, he’s dropped off substantially. It’s possible he rebounds in 2014 but the downward trend is clear – see the next chart. He might have a better curve in PPR formats and hence a better outlook – he was RB26 in non- PPR last year and RB24 in PPR leagues, so even with his drop-off, he had value as a flex player.  But he’s not likely to be an RB1 again (only Sanders and Smith had top 10 finishes of the 29&9 group; three others ranked between 11th and 13th).

 

Bush, on the other hand, was never above the 29 & 9 average until his 8th year; most years he was well below the group. He did better than MJD only in the last two seasons. With health he could stay closer to the 29&9 line in 2014, but I’d expect him to be pulled down by the inexorably deterioration of aging, despite his positive trend line:

 

 

 

That curve for Bush will turn down again soon enough.

 

To go back to the beginning of this article, I don’t think I settled the question. I’m leaning toward age being more important than experience (as a proxy for wear and tear) in explaining the inevitable decline of fantasy RBs. For MJD, the trend line is to fall out of the top 40 this year to about 6 FPG, but his last two seasons suggest a flattening into the 9-10 FPG range. Bush has some positive signs despite his age, but I’m not convinced that he can sustain his pushback against Father Time.

 

Editor’s Note: For the record, we’ve discussed age versus usage with several HOF and future HOF RBs like LaDainian Tomlinson and Emmitt Smith, and the consensus is that age is generally a bigger factor in a decline in RB production. Obviously, with more years in the league will bring more touches, so the two are related. But these RBs believe the body starts to deteriorate more due to age, as things like a RBs’ balance start to slip.    

 

Guru subscribers are 2,002% better looking than average.

Back to the top