Lots of NFL backfields are in flux heading into Week 16 with players coming right off the waiver wire and into fantasy lineups. It might be the fantasy championship, but you'll still have tough calls to make and surprising players leading you to victory. Of course, it's nice to know which players you can continue to trust and which players are one-week wonders.

Heading into Week 15, the Minnesota Vikings made it clear they want to run the football, and that's exactly what they did in a blowout victory over the Miami Dolphins. While Dalvin Cook led the way, Latavius Murray also had one of his biggest workloads of the season. Could both players have fantasy value two weeks in a row?

The Buffalo Bills played last week's game against the Detroit Lions without the services of LeSean McCoy or Chris Ivory. During the game, they lost Marcus Murphy to an elbow injury, so Keith Ford had to handle the majority of the carries. Ford could be the only healthy back heading into Week 16, which is a dicey situation to say the least.

No one should be surprised to see the Pittsburgh Steelers stick with one dominant back. Jaylen Samuels has played that role for the last two weeks in the absence of James Conner, and he's done a good job. Of course, Samuels could lose all his fantasy value if Conner is able to return in Week 16 when the Steelers face the New Orleans Saints.

To learn more about what's going on in the backfields of the Green Bay Packers, Miami Dolphins, Philadelphia Eagles, Kansas City Chiefs, New York Jets, Jacksonville Jaguars, Atlanta Falcons and Denver Broncos, check out the Week 16 B.S. Meter. The Workload Watch covers eight other running back situations that have the most fantasy implications.

Baltimore Ravens

Week 15 Workload Distribution

Gus Edwards: 43.4% snaps, 19 carries, 104 yards, 1 TD, 0 targets

Kenneth Dixon: 51.3% snaps, 11 carries, 48 yards, 0 TD, 1 target, 1 reception, 2 yards, 0 TD

Ty Montgomery: inactive

The Baltimore Ravens decided to stick with quarterback Lamar Jackson even though Joe Flacco was healthy enough to play against the Tampa Bay Buccaneers in Week 15. That was a clear sign the run-heavy offense would be sticking around, so the results of that game weren't a surprise.

Edwards continued to lead the way even though it looked like Dixon was gaining on him in the previous two weeks. Edwards got the volume and touchdown he needed to have a solid fantasy outing with 16.4 fantasy points as RB17 for the week. Since taking over for Alex Collins in Week 11, Edwards is averaging 12.5 fantasy points per game, which is on the low end of the RB2 tier.

Dixon saw his heaviest workload since Week 1, when he carried 13 times for 44 yards with a touchdown. He also had his highest snap share of the season and beat out Edwards in snaps for the first time since returning to action in Week 13. However, he remained quiet in the passing game and didn't find the end zone, so the extra work and snaps didn't produce an increase in fantasy points.

Edwards should continue to get the most volume in this backfield and likely needs a touchdown to be an RB2. Dixon is more of a risky RB3/flex since he's battling both Edwards and Jackson for touches.

Buffalo Bills

Week 15 Workload Distribution

LeSean McCoy: inactive

Chris Ivory: inactive

Marcus Murphy: 27.9% snaps, 11 carries, 35 yards, 0 TD, 0 targets

Keith Ford: 60.3% snaps, 14 carries, 46 yards, 0 TD, 1 target, 1 reception, 7 yards, 0 TD

The injury bug bit the Buffalo Bills backfield hard in Week 15. They went into their matchup with the Detroit Lions knowing McCoy (hamstring) and Ivory (shoulder) were unavailable, but by the end of the game, you had to wonder if the Bills were thinking about coaxing Thurman Thomas out of retirement.

Murphy got the start and was busy for the first half, but an elbow injury knocked him out toward the end of the first half. That forced the team to turn to its fourth-string back in Ford. In his first action, Ford didn't get much going, but considering he was on the practice squad just days before the game, his NFL debut was good enough to help the Bills get a victory.

The Bills put Murphy on injured reserve, so they'll head into Week 16 with Ford as the only healthy back. Both Ivory and McCoy were limited in Wednesday's practice, so neither should be considered a lock to play. The matchup against the New England Patriots isn't a bad one, although it would be tough to use anyone except McCoy with any confidence, and even he would be considered a shaky RB2 at best.

Chicago Bears

Week 15 Workload Distribution

Tarik Cohen: 63.3% snaps, 5 carries, 21 yards, 0 TD, 6 target, 5 receptions, 31 yards, 1 TD

Jordan Howard: 56.7% snaps, 19 carries, 60 yards, 1 TD, 1 target, 1 reception, 15 yards, 0 TD

It's been a busy few weeks for Howard, yet the fantasy production has been hard to find because he went into Week 15 on a five-game scoreless streak. Howard has been a volume- and touchdown-reliant fantasy option for most of the season, so even when he rushed for 101 yards in Week 14, he scored just 11.3 fantasy points. Luckily, his streak ended in Week 15.

Thanks to his rushing touchdown and another busy day on the ground, Howard finished with 14.5 fantasy points and a top-20 effort for the week. Over the last three weeks, Howard has 54 carries for 237 yards and a touchdown in addition to three receptions for 21 yards on three targets. He's RB19 during that span with 11.6 fantasy points per game, so the volume has been a good boost to his value.

Cohen continues to roll right along as the better fantasy option in Chicago's backfield. During that same three-game stretch, Cohen checks in at RB7 with 20.6 FPG. He hasn't been a busier runner, but he has been efficient with 120 yards on 22 carries (5.5 yards per carry) in those three games. He continues to lead the Bears in targets (87), receptions (68) and receiving yards (710) with five touchdowns through the air.

Chicago gets another favorable matchup in Week 16 when it hits the road to face the San Francisco 49ers. Cohen remains a high-end RB2 with RB1 upside, while Howard is on the RB2/RB3 borderline since he needs volume and a touchdown to be useful for fantasy.

Detroit Lions

Week 15 Workload Distribution

LeGarrette Blount: 19.3% snaps, 7 carries, 9 yards, 0 TD, 1 target, 0 receptions

Theo Riddick: 43.9% snaps, 8 carries, 47 yards, 0 TD, 3 targets, 2 receptions, 9 yards, 0 TD

Zach Zenner: 45.6% snaps, 10 carries, 45 yards, 1 TD, 4 targets, 3 receptions, 0 yards, 0 TD

Kerryon Johnson: inactive

The Detroit Lions went into Week 15 without the services of Johnson, as he sat out with his knee injury for the fourth straight week. Blount looked like the unquestioned lead ball-carrier in the first two games without Johnson, but the last two weeks have seen Zenner emerge.

It wasn't a huge lead over Blount and Riddick, but Zenner did lead the way in snaps, carries, targets and receptions on his way to 13.5 fantasy points and a top-25 finish for Week 15. That gives Zenner 22 carries for 99 yards and two touchdowns the last two weeks. He's been the best Lions running back in those games, which might make it a little easier to use him for the fantasy championship.

Blount didn't have much of a presence in Week 15, yet his seven carries are enough to limit any chance that Zenner has a huge game. He'd have to completely go away for Zenner to be considered a reliable RB2. That won't be happening with the news that the Lions finally decided to put Johnson on injured reserve. With the team long out of contention, the move seemed overdue.

Riddick isn't doing enough as a receiver to consider using even as a desperation flex option. He has just nine receptions for 65 yards on 11 targets in the last three games. Only Zenner is worth considering, and he doesn't have a great matchup with the Minnesota Vikings in Week 16.

Minnesota Vikings

Week 15 Workload Distribution

Dalvin Cook: 60.9% snaps, 19 carries, 136 yards, 2 TD, 2 targets, 1 reception, 27 yards, 0 TD

Latavius Murray: 39.1% snaps, 15 carries, 68 yards, 1 TD, 0 targets

If you're hunting for help on the waiver wire heading into the fantasy championship, you won't be alone, although your backfield may have gotten a welcome boost if you had Cook in the lineup for Week 15.

Head coach Mike Zimmer's mandate to run the ball more was not just lip service. Cook had his busiest and best game of the season in a lopsided win over the Miami Dolphins. Since returning from a hamstring injury in Week 9, Cook's carry totals were 10, nine, 10, nine and 13. The lack of volume in those five games was part of the reason he averaged 14.3 fantasy points per game during that span. He made up for the lack of carries with 23 receptions for 115 yards and two touchdowns on 27 targets.

In the first game since Zimmer's mandate, Cook came through in a big way despite doing very little as a receiver compared to previous weeks. It marked his first 100-yard game of the season and third game with at least 84 rushing yards since Week 9.

Cook wasn't the only one to get a boost from the renewed focus on the run. Murray tied his second-highest carry total of the year and had his third-best rushing performance. It was the fourth time this season both Cook and Murray hit double-digit carries in the same game, but the only time each player had at least 15 carries in the same game.

It's probably not fair to bank on Murray and Cook to each get 15-plus carries this week against the Detroit Lions, although both players could have useful fantasy value. Cook has top-10 potential while Murray could be a decent RB3/flex assuming the game flow works in his favor and allows for decent volume behind Cook.

New England Patriots

Week 15 Workload Distribution

Sony Michel: 35.5% snaps, 13 carries, 59 yards, 0 TD, 0 targets

James White: 41.9% snaps, 2 carries, 12 yards, 0 TD, 7 targets, 5 receptions, 25 yards, 0 TD

Rex Burkhead: 25.8% snaps, 4 carries, 25 yards, 0 TD, 3 targets, 3 receptions, 18 yards, 0 TD

James Develin: 32.3% snaps, 0 carries, 2 targets, 2 receptions, 18 yards, 0 TD

The New England Patriots really are picking the worst time to involve four different backs in their offense. What's even more annoying is that the split didn't even lead to a victory. Hopefully, the Patriots see the error of their ways and get back to featuring Michel and White with no significant roles or snaps for Burkhead and Develin.

Develin entered the game with four touchdowns in the previous four games, so of course, he didn't get a carry. Instead, he caught his 10th and 11th receptions of the season. The plays were successful, but it's extremely frustrating to see Develin go from stealing touchdowns from Michel to stealing targets from White.

Speaking of White, his streak of decreasing snap shares finally ended, although it didn't lead to much fantasy production. For the fourth time this season, he failed to gain at least 30 receiving yards. Unfortunately, that's happened three times in the last four weeks, so White has been a huge disappointment during the most important part of the year.

Michel's Week 15 usage might be the most disappointing of the group. He ran well when given the chance, yet the Patriots refused to stick with him for an extended period. That didn't make a lot of sense since the rest of the offense wasn't clicking and running Michel was arguably the best way to keep the Pittsburgh Steelers offense off the field. Michael has now failed to run for more than 63 yards in five of his last six games.

The presence of Burkhead and Develin is crushing the reliability of Michel and White. The Patriots could wise up and get back to featuring Michel and White this week, but it's hard to start either player with a lot of confidence in the fantasy championship.

Pittsburgh Steelers

Week 15 Workload Distribution

Jaylen Samuels: 62.5% snaps, 19 carries, 142 yards, 0 TD, 2 targets, 2 receptions, 30 yards, 0 TD

Stevan Ridley: 9.4% snaps, 3 carries, 16 yards, 0 TD, 0 targets

James Conner: inactive

When Samuels stepped in to help replace Conner in Week 14, he had 12 carries for 31 yards and seven receptions for 54 yards and two touchdowns on nine targets. The Pittsburgh Steelers could have asked a veteran like Ridley to help Samuels split the massive workload Conner handled for the majority of the season. Instead, it's been all about Samuels, and he's answered the bell (no pun intended).

Samuels wasn't very productive on the ground in Week 14 with just 28 yards on 11 carries, although he was able to make up for that with seven receptions for 64 yards on seven targets. Samuels wasn't asked to do as much through the air against the Patriots in Week 15, but he did take on a huge carry share and wound up having unexpected success.

In two games without Conner, Samuels has carried 30 times for 170 yards and has nine receptions for 94 yards on nine targets while playing 88 out of a possible 124 snaps (71 percent). By comparison, Ridley has just eight carries for 20 yards and a touchdown without a target on 14 snaps.

Samuels' dominance in the snaps and touches is important because he could be needed again in Week 16. Conner told reporters Wednesday he's "not ready yet" as he continues to work his way back from a high-ankle sprain. As long as Samuels is leading the way, he'll be a high-end RB2 with RB1 upside. Samuels and the Steelers face the Saints in New Orleans on Sunday.

San Francisco 49ers

Week 15 Workload Distribution

Matt Breida: 72.6% snaps, 17 carries, 50 yards, 0 TD, 5 targets, 5 receptions, 46 yards, 0 TD

Jeff Wilson: 19.4% snaps, 7 carries, 46 yards, 0 TD, 1 target, 0 receptions

Breida has battled through multiple injuries all season, so it shouldn't have been a big surprise to see him return to action after missing just one game. It also wasn't much of a surprise to see him take the lead role back from Wilson even though the rookie did a fine job in Breida's absence. 

Breida's 17 carries matched his season high, although it didn't amount to a lot of yards. Luckily, Breida's five receptions were also a season high, and his 46 receiving yards marked his second-highest total of the season. Unfortunately, Breida aggravated his ankle injury toward the end of the game. 

Breida got in a limited practice Wednesday, so he'll have a chance to play in Week 16. He's played through injuries all year without much practice. The San Francisco 49ers wouldn't have a problem turning back to Wilson, although he did lose a fumble in Week 15. Assuming Breida is healthy enough to play, he'll be a decent RB2 against the Chicago Bears. Wilson would only have value if Breida is inactive.

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