It had been a while, but another significant injury has caused a shift in RB values. We also have some new RBBCs forming in unexpected places and more undrafted players stirring things up. Things are getting interesting as we get closer to playoff time.

This article will aim to highlight Week 12 waiver wire adds for running backs, players that you should consider targeting on your league's waiver wire if available. Running backs will be split up into three tiers - from most desirable, to most desperate.

I will also include RBs at the bottom of this list that you might consider cutting in order to make room for your new additions and a suggested percentage of your FAAB to spend on each player.

• Quarterback fantasy football rankings
• Running back fantasy football rankings
• Wide receiver fantasy football rankings
• Tight end fantasy football rankings
• Kicker fantasy football rankings
• FLEX fantasy football rankings
• Defense (D/ST) fantasy football rankings
• Superflex fantasy football rankings
• IDP fantasy football rankings
• Dynasty fantasy football rankings

Frontrunners for Week 12 - Waiver Wire Running Backs

Samaje Perine, Washington Redskins - 32% owned (10-15% FAAB)

It appears there weren't too many Perine believers after Rob Kelley went on IR last week. As of Sunday night, Perine was still available in two-thirds of Yahoo leagues and figures to be the top add across the majority of fantasy leagues. With Chris Thompson also out for the season, he has as clear a path to playing time as possible. He responded with a breakout game, running for 117 yards and a touchdown against a tough Saints defense. Perine won't catch many balls and still must prove he can handle a full load on a regular basis, but you won't find many other work horse backs lying around the waiver wire at this point in the season. Even if you don't need another RB, try to add him just to prevent your leaguemates from gaining an advantage.

Danny Woodhead, Baltimore Ravens - 49% owned (10-15% FAAB - PPR only)

Woodhead should already be owned in most PPR leagues, but he slides in at just under 50% across all league formats and could be available. He immediately resumed his role as the pass-catching specialist, grabbing five of six targets in Week 11. He only went for 21 yards and saw just one carry for two yards, but he is likely being eased into action and the game script didn't call for too many passes. Woodhead should provide a nice floor for PPR leagues, but doesn't really need to be on rosters in standard leagues.

Devontae Booker, Denver Broncos - 7% owned (5% FAAB)

Slowly but surely, Booker is eating into C.J. Anderson's workload. He had 19 touches in Week 11, finishing with 44 yards on the ground and 54 through the air. This offense won't provide many scoring opportunities as long as Brock Osweiler is at the helm, but that could change in the coming weeks if Paxton Lynch gets a shot. It's still to be determined whether that's a good thing, but at least there's hope.

In The Running - Week 12 Waiver Wire Running Backs

Damien Williams, Miami Dolphins - 32% owned (3-5% FAAB)

You're better off not relying on anybody in Miami's running game, but if you are in need of an RB3/flex play next week even with no byes, he is an option. Williams has been just as productive as Kenyan Drake, who has more than twice the ownership level. So far this season, Williams has 143 yards rushing, 141 receiving, while Drake has 180 rushing, 62 receiving yards. Williams saw less snaps than Drake, but both players seem to be dependent on big plays for value, so it's a weekly coin flip either way.

Austin Ekeler, Los Angeles Chargers - 35% owned (3-5% FAAB)

Who has two thumbs and three touchdowns in the last two games? That would be Austin Ekeler, of course. He didn't really see the field until garbage time in the fourth quarter of an easy victory in Week 11, but he turned six carries into 40 yards and a touchdown. There's clearly some value here, especially as a handcuff play in case of a worst case scenario for Melvin Gordon owners.

Corey Clement, Philadelphia Eagles - 10% owned (2% FAAB)

How is it that an UDFA who is the third-string running back on his team can be fantasy relevant? He plays for the Eagles, that's how. On Sunday night in Dallas, Clement got just as many carries as Jay Ajayi and took more snaps. He scored his sixth touchdown of the season too. Clement isn't a terrific pass-catcher, but he is the one playing on third downs and appears to be a worthy streamer as long as Philly keeps rolling over teams.

Honorable Mentions: Theo Riddick (43% owned), T.J. Yeldon (21% owned)

Dark Horses - Week 12 Running Backs Waiver Wire

Byron Marshall, Washington Redskins - 0% owned (1% FAAB)

We have little idea what Marshall can bring to the table, as he spent the first half of the year on Philadelphia's practice squad and saw all of 19 carries last season. He'll have to become a pass-catcher if he wants a role on this team, but he's got the opportunity. It remains to be seen if he has the talent. Marshall was undrafted out of Oregon, ran a 4.61 40-yard dash and had otherwise unimpressive combine numbers. He's best left on the wire, but could be a deep league dynasty stash.

Marlon Mack, Indianapolis Colts - 29% owned (1% FAAB)

The Colts had a bye this week, so there's nothing new to report here. It will be interesting to see if the team commits to the youth movement the rest of this season now that Andrew Luck is ruled out for the year and their playoff hopes are... well, they never really had playoff hopes once this year began. Mack is averaging a paltry 3.7 Y/A, but that's still better than Frank Gore's 3.5 Y/A. He's a speculative bench stash in redraft leagues.

Rod Smith, Dallas Cowboys - 19% owned (1% FAAB)

It was interesting to see Rod Smith as the starter on Sunday night, but he only carried twice in the first half for six yards. He finished with 11 yards on eight rush attempts as the Cowboys again could muster no offense without Ezekiel Elliott. There is little reason to own Smith at this time.

Honorable Mentions: Tarik Cohen (46% owned), J.D. McKissic (8% owned), Charles Sims (1% owned)

Time To Say Goodbye

Chris Thompson, Washington Redskins - 90% owned

It looks like we'll be left wondering how effective Thompson could have been with more carries in this offense. Thompson suffered a fractured fibula against the Saints and his season is officially over. He was a revelation for PPR owners who added him early in the year; Thompson totaled 804 yards and six touchdowns on the season. There doesn't appear to be an obvious replacement for his third down role in Washington, which may wind up hurting the offense as a whole.

D'onta Foreman, Houston Texans - 7% owned

He was about to be at the top of this list after running in his second touchdown of the afternoon, but sadly he tore his Achilles after reaching the end zone on a 34-yard TD jaunt. Foreman was barely owned as of this week, but if you only saw his stat line and missed the news, don't waste your time trying to pick him up. He appears to be a good stash for dynasty owners who may consider buying low from a contender who doesn't need him.

Javorius Allen, Baltimore Ravens - 55% owned

You were warned a couple weeks ago to try selling Allen for whatever you could get once Danny Woodhead started practicing again. With Woodhead back, Allen was only on the field for 10 snaps and ran five pass routes, as opposed to 13 and 12 for Woodhead (stats courtesy of Nathan Jahnke via Twitter). Allen simply doesn't hold any more value unless there is another injury in the Baltimore backfield.

More Waiver Wire Pickups and Analysis