Which Running Backs Outperformed Their Teammates the Most in 2015?

Rushing statistics can often be misleading.

With the ability to skew a yards-per-carry mark with a big gainer here and there over a small sample (here's looking at you, Joseph Randle) and relying on an offensive line to create space with which to work, running backs -- perhaps more than other positions -- are tough to compare from team to team.

But what happens when we compare these guys to their teammates, players running behind the same offensive lines in the same offenses?

That sounded like a good idea, so I gave it a shot.

The Process

At numberFire, we have a metric called Net Expected Points (NEP), which indicates how a team or player performs in terms of adding expected points on a given play. You can read more about it in our glossary.

The league-average Rushing NEP per play in 2015 was actually -0.04, so rushing is a bad way to gain expected points. Last year, only 14 teams' collections of running backs were better than -0.04, seven were above 0.00, and six were -0.10 or worse. Throwing in some team-by-team context probably can't hurt.

Comparing individual players to their teammates' combined Rushing NEP, Rushing NEP per play scores, and Rushing Success Rates -- the percentage of carries that lead to NEP gains -- can show us which guys fared well despite poor rushing situations and which guys underperformed in otherwise efficient rushing offenses.

We have to keep in mind that some teams have weak backup running backs, but what do the numbers actually show?

The Results

Here are the 20 players with at least 100 carries who had a Rushing NEP per carry relative to their teammates of at least 0.02 last year.

Todd Gurley really stands out here. His Rushing NEP per play on the season was 0.03, which ranked fifth among 44 backs with at least 100 carries last year. The only player with a mark better than 0.08 in that group was David Johnson (0.15). Compared to his teammates, Gurley was phenomenal, and that shouldn't be surprising.

The same goes for T.J. Yeldon, though his new backfield mate, Chris Ivory, also outperformed his Jets teammates by a noticeable margin last year on a per-carry basis.

A few older guys also make the list. First, Frank Gore had flat out abysmal metrics last season. His -0.11 Rushing NEP per carry ranked 40th among 44 backs with at least 100 carries, but -- believe it or not -- other Colts running backs owned a mark of -0.27.

Justin Forsett's -0.02 was close to the league average, but his Ravens teammates yielded a -0.16. Rashad Jennings' 0.02 Rushing NEP per play outpaced the other Giants' mark of -0.10 by a significant margin.

As for some lower-volume guys, Karlos Williams, who saw 93 carries, outpaced his teammates by 0.29 Rushing NEP per rush. Spencer Ware, 72 carries, was 0.21 better than his teammates (and Jamaal Charles was 0.09 better than the rest of his teammates). Jerick McKinnon, 52 carries, saw an adjusted mark of 0.17.

Three of these guys are entrenched behind surefire starters, but if given the chance, they could flash some upside in 2016.

Because per-play numbers can be skewed a bit by those big plays, it also makes sense to examine team-by-team differences in terms of Rushing Success Rate. That way, we can see who was churning out consistent, point-boosting runs relative to their teammates. For context, the league average rate for backs was about 39% last season.

Here's the top 16 by this measure, which lets us cut off at guys with a mark of at least 3.40% better than their teammates.

To reiterate, Jennings did well last year. Since 2000, there have been only 39 instances of a running back posting a Rushing Success Rate of 50.00% or better with at least 100 carries in a season. Jennings' 50.77% and David Johnson's 50.40% made the cut this year. And if we make the cutoff 195 carries, Jennings' rate ranks 12th among 372 qualified rushers. Not bad at all.

Eddie Lacy had a largely forgettable 2015, but his 43.85% Success Rate ranked ninth among the 44 100-carry backs, which was significantly better than the 34.71% that other Packers running backs posted.

We should also note that younger backs Ameer Abdullah, Carlos Hyde, Thomas Rawls, and Lamar Miller made the cutoff for both tables.

Takeaways for 2016

Todd Gurley was a boss. That's one takeaway. But the Rams didn't do too much to improve their offense during the offseason, so he really has to overcome a weak offense again.

Some older backs -- Gore, Jennings, and Forsett -- managed to fare significantly better on a per-carry basis than their teammates, and each posted Success Rates that were significantly higher than their teammates as well. Gore still should have a stranglehold on the backfield in Indianapolis, Jennings' only new competition is rookie Paul Perkins, but Forsett has some challenges in Kenneth Dixon and Javorius Allen.

And a group of younger backs -- Abdullah, Hyde, Rawls, and Miller -- outpaced their backfield mates, but their situations aren't the same across the board. Abdullah's arrow is pointing up, and Hyde's upside could show in 2016, as well.

However, Miller is in a new -- but promising -- situation, and Rawls has competition from C.J. Prosise and Alex Collins and is still recovering from his ankle injury from last season.