Fantasy fallout: Which replacement RBs have staying power?

This was a big week for backup running backs, with fantasy ownership of Chase Edmonds, Ty Johnson and Latavius Murray all vaulting by at least 24% in ESPN leagues.

But which of these guys can you actually trust in your starting lineups in Week 8 and beyond? As always, our NFL Nation reporters are here to help sort it out.

Chase Edmonds, Arizona Cardinals: This one is a bit of a sore subject to David Johnson’s fantasy owners -- and to ESPN fantasy analyst Matthew Berry, who went on an epic rant -- because Johnson was active last week and actually took the first handoff before Edmonds went off for 126 rushing yards and three touchdowns on 27 carries.

If Johnson is ruled out this week, Edmonds is obviously a must-start. But even when Johnson is fully healthy, Cardinals reporter Josh Weinfuss thinks Edmonds has earned a significant “1B” role.

“The Cardinals were impressed with Edmonds’ route-running ability when Kliff Kingsbury and his staff first took over. They liked him from the get-go. They like that they don’t have to change the playbook when he’s on the field instead of David Johnson. And he’s shown now that he can carry the workload,” said Weinfuss, who thinks the additions of veteran RBs Alfred Morris and Zach Zenner are just for “support.”

“[When Johnson is healthy], I think David’s gonna get a few more touches just because he’s David Johnson,” Weinfuss continued. “But if he doesn’t produce, I don’t think Kingsbury would mind going with Edmonds if they start to win games and get in the playoff hunt. And they can do a lot of stuff on the field at the same time, with Johnson running more receiving routes.”

Ty Johnson and J.D. McKissic, Detroit Lions: Johnson’s fantasy ownership exploded from 1.4% to 63.9% after Lions RB Kerryon Johnson was placed on injured reserve with a knee injury. And Lions reporter Michael Rothstein expects the rookie sixth-round draft pick to get the most work now after he ran 10 times for 29 yards and caught four passes for 28 yards last week.

But Rothstein cautioned that coach Matt Patricia is planning on the dreaded running back-by-committee approach, which should also include McKissic -- who previously worked with offensive coordinator Darrell Bevell in Seattle.

So it’s worth stashing Johnson on your bench, but you might have to wait and see if you can trust him as a weekly starter.

“Johnson is more of a speed back than his predecessor in the role, but he has the ability to run between the tackles as well,” Rothstein said. “The Lions aren't saying how much each player is going to work, but Johnson's expected to get a good share of it. Beyond him, look at McKissic -- who had a role even when Kerryon Johnson was healthy. And you could take a deep flier on Tra Carson or Paul Perkins if you’re desperate, since the backfield is still full of questions.”

Latavius Murray, New Orleans Saints: Starter Alvin Kamara could return from ankle and knee injuries as soon as Sunday. But even if Kamara is fully healthy after the Week 9 bye, Murray could still have some fantasy value if you’re in a pinch.

For one thing, Kamara's injury should inspire coach Sean Payton to go back to his preseason vow that he wouldn't overwork Kamara and that he liked his "pitch count" where it was when he used to split time with Mark Ingram. And if Murray hadn’t already earned the Saints’ trust, he certainly did last week at Chicago with 27 carries for 119 yards and two touchdowns, plus five catches for 31 yards. Murray has also had two other TD runs called back because of holding penalties the past two weeks.

As ESPN’s Saints reporter, I’m not suggesting this will be the same 1A/1B duo we saw with Kamara and Ingram. But Murray has earned a true No. 2 workload at the very least. He should get more opportunities to run out the clock as the Saints’ schedule lightens up. And he would be a must-start if Kamara misses time again.

Mark Walton, Miami Dolphins: For now, Walton is still stuck in a timeshare with Kenyan Drake and Kalen Ballage. But as Dolphins reporter Cameron Wolfe wrote last week, Walton keeps earning a bigger piece of the pie. He had 14 carries for 66 yards last week at Buffalo, and he could become a bona fide No. 1 back if Drake is traded.

“Walton has ascended to the lead back in the committee after starting and leading all Dolphins backs in yards over the last two games,” Wolfe said. “Miami's coaching staff loves him. Brian Flores says he has a three-down skillset and casually dropped this week, ‘If you’re a Dolphins fan, you want to see Mark Walton get the football a little bit more.’

“Well, seeing as Flores has input on Walton's snaps, I believe that's a prediction of what to expect going forward. And he could eventually end up being a flex option if Drake is traded and the Dolphins’ offense continues to improve."

Now for the rest of our weekly tour around the league:

Cincinnati Bengals: Ben Baby broke down why RB Joe Mixon has gotten off to such a disappointing start -- and why quarterback Andy Dalton has done the same. (Yes, the offensive line is a big part.) At least there is one glimmer of fantasy hope. Receiver A.J. Green had his most productive week of practice as he recovers from his preseason ankle injury.

Cleveland Browns: The Browns are hoping Baker Mayfield can respond to adversity the way he did at Oklahoma after a poor start in 2016, wrote Jake Trotter. "I play best when I'm angry," Mayfield said after a loss to the Seahawks before the bye. "I'm pretty pissed."

Dallas Cowboys: Since joining the Cowboys one year ago, receiver Amari Cooper is 10th in the NFL in receptions, fifth in yards and second in touchdown catches, as Todd Archer noted. "It damn sure doesn't seem like he just got here," QB Dak Prescott said.

Denver Broncos: Courtland Sutton considered himself a No. 1 receiver even before veteran teammate Emmanuel Sanders was traded away this week, wrote Jeff Legwold. And now there’s no question about it.

Green Bay Packers: Receiver Marquez Valdes-Scantling laughed at the idea that Aaron Rodgers’ six-TD performance on Sunday counted as a “breakout game.” But as Rob Demovsky wrote, it has been a while since Rodgers was in the league MVP conversation.

Indianapolis Colts: Jacoby Brissett just joined Johnny Unitas, Peyton Manning and Andrew Luck as the only Colts QBs to throw for at least 300 yards and four TDs in a game without an interception, as Mike Wells wrote. "It says he's legit," coach Frank Reich said of the team’s trust in Brissett. "He's the man. We've believed that from Day 1."

Los Angeles Chargers: “Now you see me, now you don’t.” Eric D. Williams dove into running back/receiver Austin Ekeler’s ability to make defenders miss.

New England Patriots: Mike Reiss wrote that the Patriots have been looking for an inside receiver to fill the void ever since Rob Gronkowski’s retirement. “They had it with Antonio Brown, but we all know how that turned out,” Reiss wrote. Now they’re hoping they have it again after trading for veteran receiver Mohamed Sanu.

Reiss also noted that Sanu’s presence should help fellow WR Julian Edelman the most. “Some mistakenly view Edelman as a pure slot,” Reiss wrote. “But he's actually just as capable on the outside, where he still aligns almost half the time.”

New Orleans Saints: So far it hasn’t mattered who is throwing the ball to receiver Michael Thomas. He has 62 catches through seven games – threatening Marvin Harrison’s NFL record of 143 in a season. But does it actually matter who’s guarding “Can’t Guard Mike?” Arizona’s Patrick Peterson will put that to the test.

Oakland Raiders: Coach Jon Gruden said the Raiders’ trio of tight ends is the “lifeblood” of their offense, as Paul Gutierrez wrote. It starts with Darren Waller, whose 44 catches moved him past Tim Brown for the most receptions through the first six games of a season in franchise history.

San Francisco 49ers: It was “painfully obvious” that the 49ers needed reinforcements at their weakest position, wide receiver, wrote Nick Wagoner. And newly acquired veteran Sanders should be an ideal fit because he knows the offense and can play all over the formation.