Efficiency is great and all, but when it comes to fantasy football, we just need volume.
Without volume and touches, our fantasy football assets can't rack up high point totals. None of this should be a surprise to anyone who's played our game before.
But on a similar note, volume can help identify regression when we dig into running back performance. Rather than trusting that players will score touchdowns at a similar rate year-to-year, we can look deeper at the numbers and see what a player should've scored based on his yardage.
The Process
Rushing efficiency is kind of a paradox in today's NFL. According to our positive and negative regression candidates), that doesn't do us a ton of good with running backs.
But that's okay because, for running backs, volume and touchdowns are tied together quite nicely, especially when we look past just rushing and factor in receiving.
Here's how total yards and total touchdowns since 2009 (among players with at least 100 touches) looks when graphed.
Pretty linear, and the R-squared value is promising. This means that a player with 1,500 total yards should score around 9.5 touchdowns in a season, and a player with 1,000 yards should score around 6.0 times in a season.
Players who outperform or underperform expectations will be flagged as regression candidates for the 2018 season. Of course, this doesn't account for players who are red-zone threats who score at a high rate without racking up yardage.
Backtesting: 2017 Red-Flag Candidates
We will fit 2016's performance to our trendline in order to backtest this for the 2017 season.
In total, 18 backs fit the following criteria of having at least 50 touches in both 2016 and 2017 and having outperformed their touchdown expectation by a full score, based on our regression analysis.
Here is their story in 2017. (As a point of reference running backs have scored a touchdown every 32.5-or-so touches since 2009.)
| Player | Total Yards | 2016 TD | Touch/TD | 2017 TD | Touch/TD |
|---|---|---|---|---|---|
| LeGarrette Blount | 1,199 | 18 | 17.0 | 3 | 60.3 |
| Latavius Murray | 1,052 | 12 | 19.0 | 8 | 28.9 |
| Mike Gillislee | 626 | 9 | 12.2 | 5 | 21.0 |
| Tevin Coleman | 941 | 11 | 13.5 | 8 | 22.9 |
| Damien Williams | 364 | 6 | 9.7 | 1 | 66.0 |
| LeSean McCoy | 1,623 | 14 | 20.4 | 8 | 43.3 |
| Jonathan Stewart | 884 | 9 | 25.1 | 7 | 29.4 |
| Devonta Freeman | 1,541 | 13 | 21.6 | 8 | 29.0 |
| Ezekiel Elliott | 1,994 | 16 | 22.1 | 9 | 29.8 |
| Melvin Gordon | 1,416 | 12 | 24.6 | 12 | 28.5 |
| Rob Kelley | 786 | 7 | 25.7 | 3 | 22.0 |
| Carlos Hyde | 1,151 | 9 | 27.1 | 8 | 37.4 |
| CJ Anderson | 565 | 5 | 25.2 | 4 | 68.3 |
| Theo Riddick | 728 | 6 | 16.1 | 5 | 27.4 |
| Mark Ingram | 1,362 | 10 | 25.1 | 12 | 24.0 |
| DeMarco Murray | 1,664 | 12 | 28.8 | 7 | 31.9 |
| Derrick Henry | 627 | 5 | 24.6 | 6 | 31.2 |
| Matt Forte | 1,076 | 8 | 31.0 | 3 | 46.7 |
Of these 18 backs, just 2 increased his touch per touchdown mark: Rob Kelley (by 3.7) and Mark Ingram (by 1.10). It's important to note that 11 of these 18 still outperformed the league-average rate (again, roughly 32.5 touches per score) even when expected to regress by a full score.
Further, 11 of these backs also scored at least 6 times in 2017, not a bad feat. This study isn't meant to indicate busts or players whose scoring will plummet but rather to see who may have an inflated touchdown total.
Plus, some players did experience drastic drops in touchdowns and touchdown rate. LeGarrette Blount fell from 18 scores to 3 and a touchdown every 17.0 touches to every 60.3 in 2017. Damien Williams' 6 scores on 364 yards looked to be too good to be true (he should've scored only 1.8 times based on his yardage total). He scored just once on 66 touches in 2017.
2018 Regression Candidates
These 24 backs appear as players who should've scored at least 1.0 fewer times in 2017 than they actually did.
| Player | Total Yards | TD | Expected TD | Difference |
|---|---|---|---|---|
| Todd Gurley | 2,093 | 19 | 13.4 | 5.6 |
| Rex Burkhead | 518 | 8 | 2.8 | 5.2 |
| Corey Clement | 444 | 6 | 2.3 | 3.7 |
| Alvin Kamara | 1,554 | 13 | 9.8 | 3.2 |
| Mike Gillislee | 398 | 5 | 2.0 | 3.0 |
| Jonathan Stewart | 732 | 7 | 4.3 | 2.7 |
| Rod Smith | 434 | 5 | 2.3 | 2.7 |
| Tevin Coleman | 927 | 8 | 5.6 | 2.4 |
| Mark Ingram | 1,540 | 12 | 9.7 | 2.3 |
| Latavius Murray | 945 | 8 | 5.7 | 2.3 |
| Rob Kelley | 212 | 3 | 0.8 | 2.2 |
| Dion Lewis | 1,110 | 9 | 6.8 | 2.2 |
| Melvin Gordon | 1581 | 12 | 10.0 | 2.0 |
| Austin Ekeler | 539 | 5 | 3.0 | 2.0 |
| Ty Montgomery | 446 | 4 | 2.4 | 1.6 |
| Leonard Fournette | 1,342 | 10 | 8.4 | 1.6 |
| Aaron Jones | 470 | 4 | 2.5 | 1.5 |
| DeMarco Murray | 925 | 7 | 5.6 | 1.4 |
| Deandre Washington | 350 | 3 | 1.7 | 1.3 |
| Jordan Howard | 1,247 | 9 | 7.7 | 1.3 |
| Chris Thompson | 804 | 6 | 4.8 | 1.2 |
| Ezekiel Elliott | 1,252 | 9 | 7.8 | 1.2 |
| Jamaal Williams | 818 | 6 | 4.8 | 1.2 |
| Javorius Allen | 841 | 6 | 5.0 | 1.0 |
First things first: this doesn't mean that Todd Gurley is going to be a bust. Far from it. But if we had to bet, we should expect him to fall shy of 19 touchdowns, something that has been met or exceeded only 5 times by a running back over the past 10 seasons.
Rex Burkhead, Corey Clement, and Alvin Kamara each have unique receiving ability to bring to their teams, yet the math suggests that they probably scored more often in 2017 than they actually should've from an expectation standpoint.
However, the fact that Kamara and Ingram both make the list is telling. Playing for a strong offense can cure touchdown regression woes.