When Le'Veon Bell never showed up in 2018, the Steelers had to lean on James Conner, their second-year, third-round pick out of Pitt.
His 1,470 all-purpose yards and 13 touchdowns were a major boost to the offense. While Pittsburgh enjoyed seeing a local hero like Conner explode onto the scene, there still is a question as to whether Conner is the Steelers' permanent solution at the position.
There were legitimate questions coming into 2018 if Conner could make it in the NFL. He had several injuries in college, didn't show much in his rookie season behind Bell, and suffered another injury that ended his year.
All those questions went away this season as he showed his ability to run hard through tackles and create extra yardage when he was given the space. Conner succeeded much more when the Steelers let him run behind power running schemes following a lead blocker. That fit more to his collegiate style as lead blockers gave him targets to bracket.
Watch how Conner is able to keep his head up on this run, and, because of Maurkice Pouncey's pull, he sees his lane to the outside and lets David DeCastro seal the inside before accelerating for a 22-yard run:
Conner was good enough at this part of his game that he had 973 rushing yards on the season — in just 13 games — most of it coming from play designs where he could follow a lead blocker and explode behind him to the designed gap.
But when Conner had to find his own gap behind the Steelers' zone-blocking schemes, he was a little more hesitant. That hesitancy led to stalled drives and missed opportunities for Conner, and raises the question as to whether he can be the full-time starting back in the coming years.
Here he is against the Ravens when the offensive line opened up a huge hole, but Eric Weddle made the tackle in the hole to prevent Conner from making a big play. Notice how Weddle sells out to tackle Conner by putting his head down. Conner made plenty of highlights in 2018 by bouncing off safeties and linebackers who put their heads down like that, but didn't in this case because he wasn't running as hard without any lead blockers:
Conner could learn how to run behind zone schemes as soon as 2019, and did improve at that as the season went on, but the question still remains as to whether he should be the man that carries the load for the Steelers moving forward.
Conner had 266 touches in 2018 and fumbled four times, while in contrast, Bell had 406 touches in 2017 and fumbled just three times. Statistically, Conner fumbled on 1.5 percent of his touches while Bell only fumbled on 0.74 percent of his touches, meaning that Conner was a little more than twice as likely to fumble as Bell.
If the Steelers want to get back to being a strong running team and Conner is going to be the guy they rely on, giving him over 400 touches could be costly if he's not more careful with the football. At the same rate, Conner would have fumbled six times if he had Bell's 406 touches.
Fumbles can prove costly. They did when Conner fumbled late against the Browns and Broncos, and Stevan Ridley did against the Saints. The Steelers lost all three of those games. And if the Conner is touching the ball more and fumbling more, that could end up being a problem.
So should the answer be getting a brand new feature back to take over Conner's starting job? Not necessarily. In the free agency pool, the best options would be Latavius Murray, an aging Adrian Peterson or Jay Ajayi. The team could also try to bring Bell back, but regardless of what JuJu Smith-Schuster thinks should happen, that's still a longshot considering the team knows it needs to win sooner rather than later and Bell just held out for an entire year.
As for the draft, 2019 is not a strong year for running backs, but there are a few candidates that could prove interesting. Namely, Bryce Love could be a steal after his stock has dropped due to injuries, and his threat as a speed back and the problems he caused for defenses while with Stanford could prove useful in the NFL.
The answer to the Steelers' question at running back may not be finding a full-time replacement for Conner, but rather a complement to his skills. Conner is a power running back that looks to break tackles and use his physicality to overpower opponents. He's quick, but he doesn't have home run speed. If the Steelers were to find another back that could produce with that kind of speed and provide more of a boost as a receiver, maybe the increase in running back touches is evened out between two viable threats.
The Saints have provided the blueprint with how they use Mark Ingram and Alvin Kamara — Ingram being the power back while Kamara rips off the big plays with his speed. Remember Kamara's 42-yard catch-and-run where he beat Sean Davis on the angle in the Steelers' Week 16 loss? That's the element the Steelers could bring into the backfield without having to invest high at the position and keep Conner's strengths involved in the offense:
The Steelers' best hope is to add a player to the position they can count on to take care of the ball in big moments. Bell didn't just get the ball a bunch of times more than Conner, he also got the ball in crucial situations where the Steelers needed a score and could trust Bell to be the best player on the field.
Conner isn't there yet, and might not ever be. Plus, his physical running style is more susceptible to injury. So, lightening his load or finding someone else who can fill that role might be the best answer.
Final Grades: Running Backs
Here's how these will work: We will grade each unit on the team and display how the players did through each quarter of the season, with each quarter represented by four games. Our War Room series has graded players on our stars and skulls system, so it's time to add them all up and show their final marks.
Each game was graded on this scale:
Had a big play or a decent game 
Very impressive, multiple big plays
Elite performance
Gave up a big play without redemption 
Total performance was a disappointment
Horrible, inexcusable
If a player was average or unremarkable, they received no mark for that game. We have tallied all their performances to see who was the top of the class.
Valedictorian: James Conner
First Quarter: 5 1 4 Games
Second Quarter: 120 4 Games
Third Quarter: 34 4 Games
Fourth Quarter: 20 1 Game
Final Marks: 227 B
Best Game: Week 9 at Ravens
Worst Game: Week 11 at Jaguars
Conner proved to be the spark needed in Bell's absence. Without having to reinvent the offense or abandon the ground game entirely, the Steelers used Conner to his strengths — a downhill runner who worked well behind a great offensive line.
Conner's biggest areas to improve are his receiving skills and ability to create yards without the line opening up larger lanes. I wrote about how Conner did much better in power run schemes than zone schemes, and that held true to the end of the year.
However, as a receiver his chemistry with Ben Roethlisberger did grow throughout the season. Bell was often Roethlisberger's safety valve who could create extra yardage on busted plays or when a defense sniffed out the play design. Here's Conner being the delayed release, and breaking up the field just in time to give Roethlisberger a clear target and convert a first down:
Had Conner continued to do that throughout the season, there would be fewer questions about what the future might be at running back for the Steelers. But after two ugly drops in the fourth quarter against the Jaguars and getting hurt for three of the team's last four games, the door is open for the Steelers to look to add at the position.
Jaylen Samuels
First Quarter: 0 0 0 Games
Second Quarter: 00 3 Games
Third Quarter: 10 4 Games
Fourth Quarter: 70 4 Games
Final Marks: 80 B-
Best Game: Week 15 vs. Patriots
Worst Game: Week 14 at Raiders
Jaylen Samuels didn't get a chance to make his mark until late in the season when Conner was hurt. But he did have an impact on the team and looked like a viable backup option for the future. The Steelers need spell options in the backfield that can find gaps in defenses and exploit them for big plays. Samuels did that enough when he got his chance.
Watch how he runs this counter by patiently waiting in the backfield before he accelerates through B-gap and then uses his quick burst to attack that hole and make it a 25-yard gain:
Samuels' biggest weakness in 2018 was his pass blocking, which was something he never had to do at North Carolina State as the H-back, a position that served primarily as an extra receiver. If Tomlin makes a push to get Samuels up to speed as a pass protector as he did for Conner going into 2018, maybe Samuels can become a true third-down running back for the Steelers in the coming years.
Roosevelt Nix
First Quarter: 0 0 4 Games
Second Quarter: 30 3 Games
Third Quarter: 40 4 Games
Fourth Quarter: 00 4 Games
Final Marks: 8 0 B-
Best Game: Week 5 vs. Falcons
Worst Game: Week 12 at Broncos
The biggest challenge for grading Nix was that he didn't get much of a chance to impact a game. He still made his presence felt when given the opportunity, but there wasn't a single game in 2018 where he played 25 percent of the offensive snaps.
That had to be a result of the Steelers' emphasis in the passing game for Roethlisberger, because when Nix was blocking for the run, he put in the work.
Watch how Nix takes on Jamie Collins on the edge, neutralizing the Browns' best linebacker, and opening up the rest of the field for the Steelers' offensive line to plow the road for Conner to get the score:
These are the plays in which Nix can make an impact. But if he doesn't see the field more, those skills will remain on the bench.
Stevan Ridley
First Quarter: 0 0 2 Games
Second Quarter: 01 3 Games
Third Quarter: 00 4 Games
Fourth Quarter: 03 3 Games
Final Marks: 0 4 F
Best Game: Week 10 vs. Panthers
Worst Game: Week 16 at Saints
Stevan Ridley was supposed the be the wily veteran who could solve problems in the Steelers' ground game that Conner couldn't. Not only did that not ever manifest, Ridley never really impacted a game positively. His best statistical performance was against the Panthers with eight carries for 26 yards, and his only touchdown came against the Raiders.
Add his two lost fumbles and you've got a really bad year of production. He won't be back with the Steelers in 2019, and he might not be anywhere else in the league either.
Running Backs Final Grade: B
First Quarter Average: B
Second Quarter Average: A+
Third Quarter Average: C+
Fourth Quarter Average: B
The Steelers needed two very young running backs to live up the requirements of "the standard is the standard" and got just that. Both Conner and Samuels had surprising performances that helped the Steelers win crucial games in 2018, even though the team ended up missing the playoffs.
But a total of seven fumbles from the group is the biggest cause for concern moving forward. In Bell's five years playing for the Steelers he fumbled eight times. When looking to rely on a strong ground game, a team has to have reliable hands on the ball.
The Steelers will add to the running back position at some point this offseason, but whether they go for a role player that will serve as a backup or an impact player that will contend with Conner for the starting position is the question.
