We know already that not every play in football has the same expected result.

A rush on 3rd-and-20 is expected to generate something -- anything -- positive to gain a smidgen of field position. A first down on that play is a longshot, and a 15-yard gain doesn't do much, but it does look good for a yards per carry average. By comparison, a rush on 3rd-and-2 sure needs to get something positive. A three-yard carry gets it done but bogs down a yards per carry rate.

Quantifying that in the offseason can be tricky, too. Who cares about a 3-yard rush that nets a first down when some other dude is tearing off 15-yarders (even if he's basically given a 15-yard cushion to get there)?

By examining plays via their impact on expected scoring rather than raw yardage totals, our who thrived even in bad situations in 2016.

These guys, though, struggled compared to their teammates.

The Process

This is detailed more in the companion piece, which examines which backs outperformed their teammates last season, so if you want a more comprehensive view, scope that out.

We're gathering up a player's Rushing Net Expected Points and Success Rate (the percentage of carries that led to positive expected points for the team) and comparing that to teammates to see who floundered by comparison.

We're excluding NEP-swinging fumbles, too. The league average running back carry in 2016 produced a Rushing NEP per carry of -0.02 points; if you exclude fumbles, it jumps up to 0.01. The NFL average Success Rate for running backs in 2016 was 40.14%.

The Results

These are the 21 backs with at least 75 carries who were outperformed by their teammates on a per-carry basis in 2016, in terms of Rushing NEP per play.

There are a lot of names to discuss, but we'll focus mostly on the relevant backs and situations for the 2017 season.

Rob Kelley, a ninth-round pick in 12-team PPR leagues, according to FantasyFootballCalculator, has some added competition this year from rookie Samaje Perine. In 2016, Kelley notched a Rushing NEP of 0.15 on 168 carries (0.00 per rush) with a Success Rate of just 37.50%. Other Washington backs possessed a Success Rate of 43.24% behind FootballOutsiders' sixth-ranked offensive line.

Dwayne Washington struggled mightily on his 90 carries in 2016, losing 15.03 Rushing NEP (-0.17 per carry) with a dismal 26.67% Success Rate. In a loaded Detroit Lions backfield, he remains a non-factor, especially with the duo of Matt Asiata and Zach Zenner, both of whom overachieved in 2016, to take short-yardage carries.

Matt Forte had 218 carries in 2016 and turned them into a loss of 6.32 points for the New York Jets. His Success Rate was just 35.32%. By comparison, Bilal Powell added 21.62 Rushing NEP on 132 carries with an incredible 51.52% Success Rate. Jets backs other than Powell had a Success Rate of just 35.15%. Powell made the most of his situation behind FootballOutsiders' 12th-ranked line. Forte did not.

Doug Martin still has three games on his suspension to start 2017, and his 2016 performance wasn't promising. He churned out a NEP boost on just 34.27% of his 143 carries (racking up -21.64 Rushing NEP in the process). We've heard it before, but it sounds as though Martin is in peak condition this offseason. But the 2016 showing and three-game suspension (plus a Week 11 bye) is a lot to account for at his 5.01 ADP.

This is shaping up to be primarily the inverse of the list of backs who outperformed teammates last year, and that's why Terrance West makes the cut. West's Success Rate of 36.79% and -0.05 Rushing NEP per carry on 193 totes just doesn't stack up to Kenneth Dixon's 0.17 Rushing NEP per carry (on 88 attempts) and 48.86% Success Rate. Speaking of suspensions, though, Dixon is out for the first four games of the season. It's unlikely West can hold him off for the lead rusher role (especially if you factor in Danny Woodhead's presence).

Thomas Rawls is a curious case, as he should have a role in the Seattle Seahawks' backfield this year, despite the addition of Eddie Lacy. Lacy produced a Rushing NEP per carry of 0.08 and a Success Rate of 40.85% with the Green Bay Packers last year, better than the -0.05 and 36.82% marks that other Packers backs secured. Rawls, who had poor injury luck in 2016, mustered just a 28.44% Success Rate behind FootballOutsiders' 26th-ranked line, including a -0.11 Rushing NEP per carry. Seattle backs other than Rawls netted rates of -0.02 and 37.19%.

Lamar Miller also dealt with poor injury luck in 2016 -- both individually and on his offensive line. But he plodded his way to a -17.83 Rushing NEP on 267 carries (-0.07 per attempt) with just a 34.83% Success Rate. Non-Miller Houston Texans backs were on the right side of zero, with a 0.01 Rushing NEP per carry and a 42.86% Success Rate. Despite the addition of rookie D'Onta Foreman, Miller is primed to be the lead back yet again.

LeGarrette Blount heads from New England to Philadelphia, so his touchdown potential should be sapped. His 298 carries yielded an above-league-average mark of 0.02 Rushing NEP per attempt, but on a 36.91% Success Rate, Blount's efficiency was inflated by NEP-boosting plays (cough, cough, 18 touchdowns). Other Patriots backs, despite a donut in the touchdown column, produced 0.09 Rushing NEP per carry with a fantastic 52.25% Success Rate. That's absurd.

"Turbo" Bob Turbin might not get enough carries to put a dent into Frank Gore's workload in 2017, but he held a significant efficiency edge in the Indianapolis Colts' offense. Whereas Gore turned 262 carries into -2.82 Rushing NEP (-0.01 per attempt) and a 40.84% Success Rate, Turbin turned 47 totes into 13.04 Rushing NEP (0.28 per carry) on a 55.32% Success Rate behind FootballOutsiders' third-ranked line. Factor in Marlon Mack's arrival, and there are plenty of reasons to be worried that this is finally the year that Gore falls off the production cliff.

Tevin Coleman benefited from a hefty touchdown total (8) on just 118 carries, ultimately leading to 4.86 Rushing NEP (0.04 per attempt). However, he churned out positive gains on just 37.29% of those carries. Other Atlanta Falcons backs did so on 42.31% of attempts and produced a Rushing NEP per carry of 0.09. His sixth-round cost is quite expensive.

DeMarco Murray's inclusion on this list really isn't a knock on him at all. The Tennessee Titans' line ranked fourth by FootballOutsiders in 2016, and Murray still netted 0.03 Rushing NEP per carry on 292 attempts. His 44.52% Success Rate looks even sturdier. The issue is more that Derrick Henry took advantage of his attempts (0.05 Rushing NEP on 110 carries with a 45.45% Success Rate).

Flipping the format a bit, here are the 16 backs with at least 75 carries who posted a Success Rate of at least 2.5 percentage points below their teammates' rate.

As outlined in the companion piece, Charcandrick West and Spencer Ware had quite different seasons with the Kansas City Chiefs in 2016. West lost 6.37 Rushing NEP on 88 carries with just a 26.14% Success Rate. Factoring out Ware's costly fumbles, he broke even on a per-carry basis and posted a strong 44.55% Success Rate.

The list is similar overall, so there's not much reason to dig into again, but these players struggled both gaining positive points on a per-play basis and a play-to-play basis relative to their teammates in 2016.

Takeaways

As always, the prior season might not really ever tell us anything, and that's especially true when factoring in new variables and team situations.

LeGarrette Blount has never been an effective rusher, but if he gets literally every rushing touchdown the Eagles' backs generate in 2017, then he'll have a decent stat line despite his metrics. If Rob Kelley fends off Samaje Perine, then his 2016 struggles won't really matter. If Matt Forte splits touches with Bilal Powell, well, then, I'll be sad.

But when trying to figure out which backs can win out in a competition or make the most of a committee, their performance relative to their teammates is worth taking into consideration. And these guys just didn't perform well in 2016.