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# An Analysis of the Running Back Wall — 2022 Update

A couple of summers ago, I wrote an article about the “running back wall”, which is a name for the point where running back’s careers start to decline. While it was a good starting point, it was very far from perfect. The sample size wasn’t large enough, it didn’t take into account playoff touches and had some human error in some steps. In this updated version of that experiment, I tripled the sample size, included playoff touches, more data and ensured the calculations were done correctly at each stage.

In terms of the research, we’ll look at:

• Yards per touch (NFL) — To use as the point where we can find his initial decline
• Total amount of touches — Touches = hits, which is the #1 factor in a running back’s decline; this figure includes NFL regular season totals, college totals and NFL playoff totals
• Yards per touch by NFL year — To evaluate which season we see the decline start (based on the yards per touch career average); figure will italicised
• Average number of touches per season — How many times did he touch the ball per season, on average.
• After how many touches did his play decline — The sum of his NFL career touches before the initial season of his decline
• Magic Number — the total from above (after how many touches did his play decline number) plus the amount of touches from college

In terms of deciding where the decline starts, the point will be determined by when he fails to surpass his career yards per touch average for the remainder of his career.

The big number that you need to pay attention to is the magic number since after that “magic number”, their career declines, which is the entire point of this experiment.

## Data for 24 Running Backs

We will use the following 24 players for this sample (up from 8):

### Emmitt Smith

Career Y/T: 4.4

Total Touches: 6075 (5319 + 756)

Yards per Touch by NFL Year: 4.4, 4.4, 4.7, 5.6, 4.4, 4.9, 3.9, 4.3, 4.4. 4.3, 4.2, 4.1, 3.9, 3.5, 3.7

Average Number of Touches by Season: 328

After How Many Touches did his play decline: 2624

Age at Decline: 27

Magic Number: 3380

## Walter Payton

Career Y/T: 4.9

Total Touches: 5130 (4532 + 598)

Yards per Touch by NFL Year: 3.9, 4.7, 5.8, 4.9, 4.8, 5.0, 4.2, 5.0, 5.5, 4.8, 5.5, 4.8, 4.2

Average Number of Touches by Season: 333

After How Many Touches did his play decline: 3959

Age at Decline: 31

Magic Number: 4557

## Frank Gore

Career Y/T: 4.7

Total Touches: 4756 (4385 + 371)

Yards per Touch by NFL Year: 5.2, 5.8, 4.9, 5.0, 5.4, 5.2, 4.4, 5.1, 4.3, 4.6, 4.2, 4.3, 4.2, 5.0, 3.9, 3.7

Average Number of Touches by Season: 264

After How Many Touches did his play decline: 2333

Age at Decline: 30

Magic Number: 2707

Note: Despite the fact that Gore did have a season with 5 yards per touch late in his career, we can chalk that up as an outlier since 7 of the 8 seasons following the 5.1 season were below the career yards per touch average and his workload in that 5.0 season was significantly reduced compared to the previous seasons. It’s for those reasons we included that year as part of his declining years.

## Curtis Martin

Career Y/T: 4.4

Total Touches: 4828 (4221 + 607)

Yards per Touch by NFL Year: 4.4, 4.1, 4.6, 4.0, 4.2, 4.4, 4.7, 4.7, 4.3, 4.7, 3.5

Average Number of Touches by Season: 364

After How Many Touches did his play decline: 3977

Age at Decline: 32

Magic Number: 4584

## Jerome Bettis

Career Y/T: 4.1

Total Touches: 4255 (3886 + 369)

Yards per Touch by NFL Year: 5.2, 3.8, 3.7, 4.5, 4.6, 3.8, 3.8, 3.9, 4.8, 3.7, 3.5, 3.9, 3.6

Average Number of Touches by Season: 283

After How Many Touches did his play decline: 2958

Age at Decline: 30

Magic Number: 3327

Career Y/T: 4.9

Total Touches: 4429 (3657 + 772)

Yards per Touch by NFL Year:

Average Number of Touches by Season: 236

After How Many Touches did his play decline: 2741

Age at Decline: 28

Magic Number: 3513

Career Y/T: 4.9

Total Touches: 4940 (3954 + 986)

Yards per Touch by NFL Year: 4.0, 4.8, 5.7, 4.5, 4.7, 5.8, 5.2, 4.5, 3.6, 4.7, 6.2

Average Number of Touches by Season: 345

After How Many Touches did his play decline: 2918

Age at Decline: 29

Magic Number: 3904

Note: The season where he had 6.2, he only had 117 touches on the season, which was significantly less than any of the other seasons in his career, so the number looks like an outlier because of the low totals.

## Barry Sanders

Career Y/T: 5.3

Total Touches: 4071 (3526 + 546)

Yards per Touch by NFL Year: 5.8, 6.1, 4.8, 4.6, 4.7, 5.8, 5.2, 5.1, 6.4, 4.7

Average Number of Touches by Season: 341

After How Many Touches did his play decline: 3146

Age at Decline: 30

Magic Number: 3692

## Edgerrin James

Career Y/T: 4.5

Total Touches: 4253 (3714 + 539)

Yards per Touch by NFL Year: 5.0, 5.1, 4.9, 4.0, 4.3, 5.3, 4.6, 3.7, 4.1, 4.1, 2.9

Average Number of Touches by Season: 315

After How Many Touches did his play decline: 2729

Age at Decline: 28

Magic Number: 3268

## Marcus Allen

Career Y/T: 4.9

Total Touches: 4947 (3929 + 1018)

Yards per Touch by NFL Year: 5.5, 4.8, 5.7, 5.2, 4.8, 4.6, 4.4, 5.4, 4.5, 5.4, 6.1, 4.2, 4.6, 4.7, 4.7, 4.4

Average Number of Touches by Season: 226

After How Many Touches did his play decline: 2741

Age at Decline: 33

Magic Number: 3759

## Eric Dickerson

Career Y/T: 4.7

Total Touches: 4253 (3444 + 809)

Yards per Touch by NFL Year: 5.0, 5.6, 4.4, 4.7, 4.8, 4.8, 4.4, 4.2, 3.9, 4.0, 4.7

Average Number of Touches by Season: 298

After How Many Touches did his play decline: 2475

Age at Decline: 29

Magic Number: 3284

## Franco Harris

Career Y/T: 4.4

Total Touches: 4115 (3707 + 408)

Yards per Touch by NFL Year: 5.9, 3.9, 5.2, 5.0, 4.1, 3.9, 3.7, 4.9, 4.1, 4.4, 5.0, 4.1, 2.5

Average Number of Touches by Season: 251

After How Many Touches did his play decline: 2606

Age at Decline: 29

Magic Number: 3014

Note: Harris had a season of 5.0 after his initial decline, but that’s because he got injured and played several less games than he normally would.

## Tony Dorsett

Career Y/T: 4.9

Total Touches: 4887 (3682 + 1205)

Yards per Touch by NFL Year: 5.4, 5.2, 5.0, 4.6, 5.3, 4.6, 4.9, 4.7, 5.0, 4.9, 4.2, 4.2

Average Number of Touches by Season: 278

After How Many Touches did his play decline: 2774

Age at Decline: 32

Magic Number: 3984

## John Riggins

Career Y/T: 4.2

Total Touches: 3950 (3166 + 527 + 257)

Yards per Touch by NFL Year: 4.6, 5.1, 4.1, 4.6, 5.1, 4.1, 4.0, 4.7, 4.6, 3.8, 3.2, 3.6, 3.8, 3.8

Average Number of Touches by Season: 226

After How Many Touches did his play decline: 1893

Age at Decline: 32

Magic Number: 2420

## Lesean McCoy

Career Y/T: 5.0

Total Touches: 3696 (3047 + 649)

Yards per Touch by NFL Year: 4.8, 5.9, 5.1, 4.8, 5.9, 4.3, 5.1, 5.7, 4.6, 3.9, 5.0, 5.3,

Average Number of Touches by Season: 248

After How Many Touches did his play decline: 2327

Age at Decline: 29

Magic Number: 2976

Note: McCoy only had 25 touches in his final season so the 5.3 figure is misleading.

## Marshawn Lynch

Career Y/T: 4.6

Total Touches: 3523 (2965 + 558)

Yards per Touch by NFL Year: 4.4, 4.5, 4.3, 3.9, 4.5, 5.3, 4.7, 5.3, 4.0, 4.6, 4.4, 2.8

Average Number of Touches by Season: 228

After How Many Touches did his play decline: 2469

Age at Decline: 29

Magic Number: 3027

## Marshall Faulk

Career Y/T: 5.3

Total Touches: 4668 (3820 + 848)

Yards per Touch by NFL Year: 4.9, 4.5, 4.0, 4.9, 5.4, 7.1, 6.6, 6.3, 5.1, 4.4, 4.4, 5.3

Average Number of Touches by Season: 300

After How Many Touches did his play decline: 2866

Age at Decline: 29

Magic Number: 3714

## Steven Jackson

Career Y/T: 4.7

Total Touches: 4067 (3258 + 809)

Yards per Touch by NFL Year: 5.6, 4.6, 5.4, 4.6, 4.8, 4.6, 4.3, 4.9, 4.6, 3.9, 4.1, 3.2

Average Number of Touches by Season: 269

After How Many Touches did his play decline: 2529

Age at Decline: 29

Magic Number: 3338

## Thomas Jones

Career Y/T: 4.2

Total Touches: 4003 (3123 + 880)

Yards per Touch by NFL Year: 4.0, 4.0, 3.9, 5.0, 4.6, 4.3, 4.1, 4.0, 4.7, 4.3, 3.9, 3.3

Average Number of Touches by Season: 249

After How Many Touches did his play decline: 2700

Age at Decline: 32

Magic Number: 3580

## Warrick Dunn

Career Y/T: 4.8

Total Touches: 4060 (3353 + 707)

Yards per Touch by NFL Year: 5.5, 4.7, 4.7, 5.3, 4.4, 4.7, 6.2, 4.8, 5.3, 4.3, 3.6, 4.8

Average Number of Touches by Season: 265

After How Many Touches did his play decline: 2548

Age at Decline: 31

Magic Number: 3255

## Eddie George

Career Y/T: 4.0

Total Touches: 4108 (3362 + 746)

Yards per Touch by NFL Year: 4.3, 4.0, 4.2, 4.8, 4.3, 3.5, 3.7, 3.6, 3.7

Average Number of Touches by Season: 348

After How Many Touches did his play decline: 2080

Age at Decline: 28

Magic Number: 2826

## Earl Campbell

Career Y/T: 4.4

Total Touches: 3219 (2448 + 771)

Yards per Touch by NFL Year: 4.8, 4.7, 5.2, 3.9, 3.8, 4.4, 3.3, 4.4

Average Number of Touches by Season: 289

After How Many Touches did his play decline: 1222

Age at Decline: 26

Magic Number: 1993

## Thurman Thomas

Career Y/T: 4.9

Total Touches: 4804 (3764 + 1040)

Yards per Touch by NFL Year: 4.8, 5.3, 5.7, 5.8, 5.7, 4.2, 4.3, 4.2, 4.2, 4.6, 5.1, 4.8, 5.1

Average Number of Touches by Season: 258

After How Many Touches did his play decline: 1886

Age at Decline: 27

Magic Number: 2926

Note: Two seasons late in his career at 5.1 were seasons were his touches were significantly reduced so they don’t accurately reflect his performance.

## Jamal Lewis

Career Y/T: 4.5

Total Touches: 3429 (2763 + 140 + 526)

Yards per Touch by NFL Year: 4.9, 5.0, 5.5, 4.6, 3.6, 3.8, 4.7, 3.9, 3.9

Average Number of Touches by Season: 307

After How Many Touches did his play decline: 2450

Age at Decline: 29

Magic Number: 2976

## Putting all the Numbers Together — Magic Number

Magic numbers by player:

Emmitt Smith — 3380

Walter Payton — 4557

Frank Gore — 2707

Curtis Martin — 4584

Jerome Bettis — 3327

Adrian Peterson — 3513

LaDainian Tomlinson — 3904

Barry Sanders — 3692

Edgerrin James — 3268

Marcus Allen — 3759

Eric Dickerson — 3284

Franco Harris — 3014

Tony Dorsett — 3984

John Riggins — 2420

Lesean McCoy — 2976

Marshawn Lynch — 3027

Marshall Faulk — 3714

Steven Jackson — 3338

Thomas Jones — 3580

Warrick Dunn — 3255

Eddie George — 2826

Earl Campbell — 1993

Thurman Thomas — 2926

Jamal Lewis — 2976

Average: 3334

Standard Deviation: 600

Range: 2744-3933

## Putting all the Numbers Together — Age at Decline

“Age at Decline” number by player:

Emmitt Smith — 27

Walter Payton — 31

Frank Gore — 30

Curtis Martin — 32

Jerome Bettis — 30

Adrian Peterson — 28

LaDainian Tomlinson — 29

Barry Sanders — 30

Edgerrin James — 28

Marcus Allen — 33

Eric Dickerson — 29

Franco Harris — 29

Tony Dorsett — 32

John Riggins — 32

Lesean McCoy — 29

Marshawn Lynch — 29

Marshall Faulk — 29

Steven Jackson — 29

Thomas Jones — 32

Warrick Dunn — 31

Eddie George — 28

Earl Campbell — 26

Thurman Thomas — 27

Jamal Lewis — 29

Average: 29.5

Standard Deviation: 1.8

Range: 27.7-31.3

## Reading the Data

### Touches

In terms of touches, we saw the the average running back wall figure was at 3334 touches. That means that after 3334 touches, we can expect to see a drop from an average running back (from our sample). The standard deviation was 600 which means that the majority of the declines will happen after the 2774th touch and before the 3934th touch.

### Age

In terms of age, we saw that the average age of decline is 29.5 years old. In terms of standard deviation, we saw it was 1.8, which means that the majority of the declines will happen within the ages of 27.6 and 31.4 years old (call it 28 and 31 years old).

## What this means for Jonathan Taylor

If we use 3330 as the running back wall number, then Jonathan Taylor has quite a few good years left in him.

Taylor had 968 touches in college and has had 663 over the first two years of his career. That puts him at 1631 total touches. You could say that at 3330 touches, he has around 1670 good touches left in him. If we use the lower end of the range, then he has 1113 touches left and if we use the higher end he has 2302 touches left.

Jonathan Taylor has averaged 340 touches (if you project for a 17 game season) over the first two years of his career. If he continues at the pace then:

• Average — 3300 Total Touches: He has about 5 good seasons left
• Low End — 2744 Total Touches: He has 3.4 good seasons left
• High End — 3933 Total Touches: He has 6.9 good seasons left

Barring any type of serious injury, Taylor has at least 3 and a half good (for him) seasons left in him before we can expect any type of decline. He has at most 7 good seasons left in him. You can expect the actual result to land somewhere in the middle which is why I project he has 5 good seasons left in him.

He is entering the 3rd year of his rookie contract. He has 2 years left on the contract. Taylor definitely deserves to see a 2nd contract, but when should he be signed until. If the Colts want to see those 5 good seasons plus potential one extra year (to see if he falls in the higher end of the running back wall range), then they’ll look to sign him to a 4 year contract after his current deal expires.

That means that next summer, Chris Ballard could look to negotiate a 4 year contract extension that kicks in during the 2024 season. Anything beyond 4 years and the Colts could be opening themselves up to a potential contract issue well down the line. Anything earlier than 4 years and Taylor could actually see a third contract with the Colts.

If we account for age, signing Taylor for 4 years after his rookie contract would lock him up through 2027, where he will be 28 and turning 29 when he is a free agent. So in terms of age, a 4 year deal after his rookie contract would time things up perfectly since that is around the age where the decline starts.