When can we expect RB dropoff to occur?

In an effort to dissect the world of Fantasy running backs, I will be writing a four-part series on how the position has been used over the past three decades. I will look at when feature running backs start their decline and if there is a “career carries” threshold, besides just age, that could predict “slowing” stats.

The four parts will include this one, about when Fantasy RBs from the ’90s dropped off, as well as:

• Pt II: 2000s Fantasy RB drop-offs
• Pt III: Multi-purpose running backs (introduce total touches)
• Pt IV: Current RBs and expected drop-off

In writing this series there will be a few questions that will get answered.

• Is there a career rushing attempt threshold to predict RB drop-offs?
• Is there a year-to year rushing attempt average to predict RB drop-offs?
• Do players from different decades differ in drop-off age?
• Do multi-purpose backs decline sooner than typical RBs?
• Are the current, trendy two-back RB systems extending the careers of feature backs?

For the first part, I went back and looked at the rushing leaders beginning in 1990. I tried to focus on the running backs that had consistent success year in and year out until they finally dropped off. Some of the running backs used had success in both the mid-to-late ‘90s and early ‘00s and were used in the decade I found fit and to keep balance.

Of course, all running backs during this time frame were not included and, as previously mentioned, I tried sticking to top performers across numerous seasons. The list of running backs researched for the first part of this series was:

*All stats were found at www.pro-football-reference.com

Average Stats Before RB Dropoff

• Total Carries – 2,744
• Yearly Carries – 302
• Yearly Yards – 1,252
• Age – 29.85

Average Stats After RB Dropoff

• Total Carries – 488
• Yearly Carries – 174
• Yards – 638
• Age – 30.85

*Three players were not included in the chart and averages:

Barry Sanders, retired before statistical drop-off

Robert Smith, retired before statistical drop-off

Terrell Davis, only had 1,343 total carries before drop-off and I felt only four seasons was not enough to include. He did, however, average 335 carries during his four peak seasons.

What can we learn about an RB dropoff?

In conclusion, there were some interesting findings from the research. For the running backs of the ‘90s, they carried the ball a ton during their prime statistical seasons. On average, they carried the ball a total of 2,744 times before their statistical drop-off season, and averaged 302 carries per season.

We will see how these numbers compare to the other decades in the next series of blogs (spoiler alert, these numbers are high in comparison and much higher than today’s current players).

Only one player had fewer than 2,200 total carries, and only two had less than 2,500. Stating that in this time frame having a total of 2,500 carries, averaging 300 per season or being 30 years are all safe predictors of a statistical drop-off in a running back’s career.

The “30 year old” mark has been stated before and this research stayed true to that. This is only the first part of the four-part running back transformation series, and after we have a larger sample size stretching across decades, the running back statistical drop-off and fantasy impact picture will be clearer.

Continue here to read Part II: 2000s Fantasy RB Dropoffs at NumbersNeverDie.com

Gary Krysztof does statistical analysis on his blog, NumbersNeverDie.com, where he tries to dig deeper into sports and the numbers that surround them.