Medians; carries 1,800, drop-off carry 1,600, difference 310

The indicator here is between 1,700 and 2,000 carries. This indicator seems a bit flimsy since 10 of the 24 backs on this list were productive beyond the 2,000 carry mark.

One interesting thing I took not of with this particular data set was the quick fall from grace running backs seem to have once they hit that drop-off in production indicated by the difference category. This means that the average back will only play for one season after they hit that dreaded drop-off carry.

Here’s a look at the active running backs in the same statistical grouping.

When I first saw the evidence presented in this data I had the idea to try and see if there were any other statistical indicators to predict when a back would see a drop off in production. The process was arduous, but hopefully the insight gained can give fantasy leaguers another reliable tool when drafting.

Who to look at?

The first step was to determine the focus group to look at. I decided on backs that played in the 1990s because that is the beginning of the golden age of fantasy football and because going back before that would be looking at a lot of backs who didn’t have the luxury of continuing their careers after a major knee injury. I decided to look at backs that had accumulated over 5,000 career yards. A good percentage of them would have been considered to top flight or at least reliable, running backs during their careers and would be looked at as a RB1 (first or early second rounds pick in a 12-team league) on a fantasy team at some point. The results include 24 retired ball carriers, 13 active players with over 5,000 yards and five active players with over 4,000 career yards (who are very likely to eclipse the 5,000 yard mark this year).

*Note: All lists are sorted by career rushing yards.

Modern era (1990-present) running backs with over 5,000 career yards

I decided to eliminate Mike Alstott, Marion Butts and Michael Pittman from the list because they would have never been considered a RB1 in any circumstance. Some might argue Adrian Murrell and a few others shouldn’t be considered, but I was involved in fantasy football back then. I remember many people being high on Murrell, especially after his third consecutive 1,000 yards season in 1998. I basically have used the criteria that if they were considered a first or second round selection in a fantasy draft, they should be included in the study.

Where to look?

The next step was to figure out what statistics to target. I wanted to be extensive, so I included some things that may be considered rudimentary. The stats I chose are as follows: height, weight (I should mention I threw these first two factors out because they didn’t seem to matter at all), seasons played, retirement age, carries (including single season high and 300 carry seasons) and career rushing yards. I also decided to track what I dubbed as a running back’s peak stretch. This was a bit subjective as different running backs have different peaks, but all players on this list had at least one season that they could consider a peak year. Looking at this peak stretch as I call it, allowed me to look for a few other indicators such as; drop-off age, drop off carry number, peak stretch (the number of years a running back maintains peak production) and the number of carries per season during their peak.

The results

Age:

As you can infer from this data past suspicions are proven correct. Most ball carriers days are numbered once they get near 30 years of age. The medians for this data are nearly identical to the averages as well; 32 for retirement age and 29 for drop-off age.

What can we take from this while looking at the low numbers of productive seasons at 30-years of age or older all running backs that are 29 or older should be severely down graded.

This is something most fantasy football veterans already know, so let’s delve further into the data and look at the active running backs numbers as they stand in the same statistical set to see what players should be red flagged for age.

*Note: ages will reflect how old the player will be at the start of the 2008 season Sept. 4.

Five of the running backs on this list have already surpassed their statistical peak and their drop-off ages are filled in. Six others have reached or will reach the dreaded age of 29 by opening day. I wouldn’t say immediate downgrades for all of them are mandatory, but if they have a few more red flags it’s time to push them down on your board.

Red Flags: Fred Taylor, LaDanian Tomlinson, Jamal Lewis, Thomas Jones, Travis Henry, Deuce McAllister and Brian Westbrook.

*Note: I am not including any players in the red flag list that have already experienced a significant drop-off in production for more than one full season.

Carries and yards:

Four backs who haven’t already hit their drop-off carry number are above the 1,700 carry red flag and another is very near it. Even though I don’t think it is a huge red flag it is still something to be concerned about.

Red Flags: Fred Taylor, LaDainian Tomlinson, Jamal Lewis, Clinton Portis and Thomas Jones (I know he’s not quite there, but I’m adding him because he’s so close).

Peak stretch:

Medians; number of peak years 5, carries per season during peak 300

What we can infer from this is that no back in the last 20 years has put out more that 10 highly productive seasons and a typical top tier back will have just half that. The carries per year during a runner’s peak don’t seem to indicate much of anything, but I thought I’d include it in case anyone else saw a trend.

Here are the active running backs numbers for the same statistical indicators.

Many of the elite, or formerly elite, active ball carriers are close to or already have accumulated five seasons of peak production. Many of the active backs have also had their peak stretches of production interrupted by an injury, but eventually recovered to regain that high level of play. When this happens it seems that the player returning from the injury can only maintain a peak level of production for one to three seasons. This holds true when looking at the list of retired players as well.

Red Flags: Fred Taylor, LaDainian Tomlinson, Jamal Lewis and Clinton Portis.

Single season carry numbers

If a back reaches his career high in caries the year before you might want to downgrade that back slightly, unless he’s only played for three seasons or less since they haven’t experienced much wear and tear yet. I’ve already outlined the ramifications of a ball carrier carrying the ball too many times as outlined in the opening chart in this article.

Here are the active running backs numbers for the same set of numbers.

Red Flag: Brian Westbrook is the only back on this list coming off a career high in carries, but since his career high number is so low makes it a little less damning. LaDainian Tomlinson and Jamal Lewis are the only two backs to get red flagged for too many 300-carry seasons.

300 carry seasons:

The 300-carry indicator seems to have some fairly conclusive data. The median and average for top tier backs is three and many seem to make it to four. Only five of the 24 backs listed made it beyond four straight seasons of 300-carries, so I feel fairly safe at setting the red flag number for consecutive seasons of 300-carries at four.

Here are the active running backs in the same category.

The final score

So how do we interpret all of this information? I belive not all these red flags are created equal. I would say the age, career carries, reaching a single season high in carries and number of 300 carry seasons are the more troubling indicators, with the number of peak seasons indicator being less concerning.

I would also infer that each red flag is a definite reason for concern, but it isn’t quite enough to downgrade a particular player. Multiple red flags on the other hand will lead me to immediately downgrade a particular back.

Here is a list of the active backs that have not yet suffered a drop off that have been red flagged based on this data.

LaDainian Tomlison:

Red flagged in all categories except reaching a single season career high in carries. This has to at least merit a slight downgrade for one of the most reliable backs in the history of fantasy football. His injury in the playoffs is also just another troubling indicator that the days of Tomlinson’s dominance are nearing an end. It may not be this year, but I’m less willing to take my chances with him than I was before seeing this data.

Fred Taylor:

Red flagged for age, career carries and having more than five peak seasons. Taylor’s age and injury history have always been troubling and people downgrade him for that significantly. I don’t think I’ll drop him much further on my own boards, but this data make me eliminate him as an option as a RB2.

Jamal Lewis:

Red flagged for age, career carries and having five or more peak seasons.

Lewis had a major resurgence last season. I’ve been saying all along that it reminded me a bit of Curtis Martin’s last hurrah in 2004. For me this eliminates any chance that I’d rely on Lewis as an RB1 and makes me very shaky on him as anything more than a third round selection in redraft leagues.

Brian Westbrook:

Red flagged for age and reaching a single season career high in carries. These are fairly troubling and may make me drop him below the likes of Joseph Addai and Steven Jackson in a redraft league.

Clinton Portis:

Red flagged for career carries and having five or more peak seasons. I have Portis ranked higher than many other experts at this point. The revelations of this data may have me rethinking that. I’ll be dropping him into the teens on my ranking and will be less likely to take him as an RB1.

Thomas Jones:

Red flagged for age and career carries. Jones has never really been considered as an RB1 and at his age he never will be. The concern over his age and the wear and tear he’s accrued over the past few seasons is troubling and may bump him down a round or two in my eyes, although I didn’t consider him as much more than a mid round pick before looking at the data.

Travis Henry:

Red flagged for age. Henry has been frustrating fantasy owners for some time. At two different points in his career he’s been considered a top 20 pick and has eventually disappointed those that drafted him. At this point he’ll never be more than a mid round selection so his red flag does little to affect his stock.

Deuce McAllister:

Red flagged for age. Couple this red flag with two severe knee injuries and you have major reason for concern. McAllister is already seen by most as a RB3/4 and an seventh/eight round pick, but I would hesitate drafting him unless it was as a handcuff for Reggie Bush.

One last disclaimer

To finish this piece off I want to say that this is still a slightly experimental process and is far from foolproof. In no way am I saying that you should take any of these players off your draft board, in fact, I’ve never been one to advocate such a close minded approach. I do hope that this study has helped you gain some insight into the shelf life of running backs in fantasy football terms.

Stick@thenflunderground.com