Top free-agent running backs and fullbacks
Take a look at Andrew Mason's top options at running back and fullback for when free agency begins in a few short weeks. (Photos by AP)

As the only player in NFL history with at least 6,000 yards from scrimmage and an average of 128 or more yards per game in his first four seasons, Bell will be coveted -- if the Steelers let him hit the market. The franchise-tag figure for running backs is expected to come in at around $9.7 million -- a perfectly reasonable figure for a runner of Bell's quality. It would be a shock if the Steelers don't use it on the two-time Pro Bowler.

Is his 2016 ankle injury a sign that pre-draft injury concerns have caught up to him, or was it a blip? The answer will depend on how well he rehabs -- and what sort of shape he is in once his recovery is complete.

He's productive and a solid No. 1 running back, but you'd like to see more consistency; in 39 career games with at least one carry, he's mustered more than 4.0 yards per attempt in just 18 of them.

He probably isn't full-time starter material, but his strong, determined work in relief of Doug Martin last season and relatively low mileage should give the 5-foot-6 back an NFL home for the foreseeable future.

Last year marked his first 1,000-yard season since 2010, but it took 299 carries for him to break four figures, as he averaged fewer than 4.0 yards per carry for just the second time in his seven-season career. He's a goal-line monster, scoring 18 touchdowns, but the best fit for him -- by far -- is the team for which he currently plays.

Crowell was often all that separated the Browns' offense from disaster last season, racking up 1,271 yards from scrimmage while averaging 4.8 yards per rush and 8.0 yards on his 40 receptions. But he had a tendency to get most of his yards in clumps; ProFootballFocus.com pointed out that 47.5 percent of Crowell's rushing yardage last year came on 16 carries.

If you owned LeSean McCoy in fantasy, you probably cursed Gillislee's name a few times last season, as he scored nine touchdowns -- one for every 11 touches he had. He was the perfect complement to McCoy -- explosive, elusive and reliable. He fumbled just once in 110 touches.

The Ravens' leading rusher is a restricted free agent who might not get a high tender with Kenneth Dixon waiting in the wings. West isn't a chain-mover, but is sturdy between the tackles.

Bengals head coach Marvin Lewis has indicated he wants to bring Burkhead back, and with an average of 4.6 yards per carry and 8.5 yards per reception last year, he's delivered in limited work. Someone might be willing to give the 26-year-old Nebraska product a greater role than Cincinnati can.

Age (32) and a torn ACL work against him, and he has now missed 27 of the last 48 games because of various injuries. When healthy, he's still arguably the best receiving running back in the game. In his four seasons in San Diego under then-head coach Mike McCoy, he averaged 4.5 receptions per game, the second-most of any running back with at least 100 catches since 2013.

In 2015, the Steelers had no dropoff when forced to turn to Williams when Le'Veon Bell was injured. He's still reasonably productive when needed, and he is a quality locker-room presence, but he turns 34 in April.

Declining production and advancing age (33 next month) led the Giants to release him this week. Jennings' historically steady production dipped last year, and although he has just seven career fumbles in 1,221 career touches, he might have to wait a while for his next contract.

Muppets jokes aside, the 28-year-old Whittaker has always been productive in limited work, and had a career-best 491 yards from scrimmage on 57 attempts and 25 receptions last year.

A torn Achilles tendon ended his 2016 campaign in the preseason, but if he recovers, the Chargers seem likely to bring him back, especially with Woodhead expected to hit the market.

Turbin was effective as a target out of the backfield for the Colts last year, and might have added another two or three years to his career by showing what he could do in space as a receiving target.

In the last two years, he hasn't recaptured his production from the 2013-14 seasons with the Buccaneers, when he was a dependable relief option for Doug Martin. He's relatively fresh, but turns 30 during the season.

He's trending in the wrong direction, with steadily declining production following a rookie season in 2013 in which he gained 1,023 yards from scrimmage on just 157 touches (a 6.52-yard average). Last year, he averaged just 3.93 yards per touch -- and 2.82 yards per carry.

He's effective catching passes out of the backfield, but a career 3.5-yards-per-carry average -- including 3.3 in 2016 -- means he's only viable as a backup option.

Despite 7,537 career yards from scrimmage in nine seasons, his career remains one of the great might-have-beens in recent NFL history, as he hasn't been the same since foot problems struck in 2011. McFadden's average per carry has hovered at 3.6 yards or worse in four of his last five seasons.

He's just a year removed from leading a world champion in rushing, and should eventually land in someone's camp with a shot at joining their rotation.

The complete package at fullback. Baltimore began finding more ways to use him in 2016 and whether he returns to the Ravens or moves on, the team that adds him will likely incorporate him into the offense as much as possible, since he's a quality target as well as a devastating blocker.

LeGarrette Blount owes Develin a debt of gratitude for giving just enough space for the tailback to score 18 times this year, most from short-yardage situations with Develin as the lead blocker.

A 31-yard reception in the NFC Championship Game showed DiMarco's skills with the football, and his blocking was an underrated aspect of the Falcons' powerful 1-2 backfield punch of Devonta Freeman and Tevin Coleman.

New Bills offensive coordinator Rick Dennison likes to utilize the fullback, and if he doesn't like his chances of finding a free-agency upgrade, there's ample reason to bring Felton back, starting with the production of LeSean McCoy and Mike Gillislee working behind him.

The Seahawks need all the quality blockers they can find -- even if they aren't on the offensive line -- so bringing back the 31-year-old former Raiders standout seems like a logical move.

A converted tailback, Line was less effective last year without Adrian Peterson in the backfield -- which is understandable. Minnesota could opt to get younger and look for more power from the position.