A couple of castoffs emerged with big days in Week 6. Now widely owned, Terrance West went from early-season waiver fodder to fantasy star. After being counted out by most fantasy evaluators, including yours truly, Jay Ajayi came up huge in a game he wasn't even supposed to start. You never know when the next breakout performer will emerge, so it's always wise to stay one step ahead of the competition by being proactive.

This article will aim to highlight Week 7 waiver wire adds for running backs, players that you should consider targeting on your league's waiver wire. 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.

Editor's Note: Once you're done here, be sure to read about even more Week 7 waiver wire recommendations, for all fantasy-relevant positions. Just click on any link: ALL - RB - WR - TE - QB - DEF - FAAB - CUTS

Frontrunners for Week 7 - Waiver Wire Running Backs

This group consists of running backs that I would recommend adding if they are available on your waiver wire. Some are more viable for PPR formats, so take note of that. These players have either earned a greater workload due to injury/performance issues or have shown that they can be weekly contributors to their NFL teams. All players listed have 50% or less ownership levels across fantasy leagues.

Jay Ajayi (RB, MIA) - 30% owned - So much for the return of Arian Foster. Technically he did return, but was not in the starting lineup and carried the ball just three times. Enter Jay Ajayi, who had never even run for 50 yards in a single game in his brief NFL career. Ajayi proceeded to shock everyone (especially the Steelers) by running for 204 yards and two touchdowns. After a performance like this, the huge question lingers: is this a sign of things to come or just a career day? He is certainly worth adding but whether he is worth actually playing is a huge conundrum for Week 7. The Dolphins will face a tough Bills defense next week and Arian Foster could see more time on the field.

Devontae Booker (RB, DEN) - 27% owned - No, there is nothing wrong with C.J. Anderson. That hasn't stopped the Broncos from gradually increasing Booker's workload over the last couple of weeks. Booker actually outrushed Anderson on Thursday night with 46 yards on just five attempts. Clearly, the Broncos see something in Booker that has earned him more snaps. Keep in mind that Ronnie Hillman ran for 863 yards and seven TD last season after taking the job from Anderson. There is enough upside here to make Booker worth a stash in any league.

Chris Ivory (RB, JAX) - 43% owned - His final rushing numbers weren't overly impressive (11 CAR, 32 YDS) but he did reach the end zone for his first TD as a Jag. Ivory is still a worthy stash, given the fact he is available in half of fantasy leagues where the state of starting running backs is precarious at best. Look for Ivory to increase his workload over the second half of the season and retain his role as the primary goal-line back. He is less valuable in PPR leagues, but standard league owners should look to own a share while you have the chance.

In The Running - Week 7 Waiver Wire Running Backs

This group consists of running backs widely available on the waiver wire who aren't must-adds, but could be worth stashing or streaming if the above options are already taken.

Mike Gillislee (RB, BUF) 6% owned - Shady's backup was just that on Sunday, carrying the ball six times. He produced 60 yards and a touchdown thanks to a 44-yard scamper in garbage time at the end of Sunday's rout against the 49ers. He won't have much stand-alone value, but the effectiveness of the Buffalo running attack and LeSean McCoy's temporary injury scare serves as a reminder that Gillislee should be a valued handcuff.

Jacquizz Rodgers (RB, TB) - 22% owned - Starter Doug Martin should be back after the bye week, but Charles Sims is on IR. Rodgers will at least have a role on passing downs and as a change of pace. Martin has not proven to be the most durable, so it's worth holding onto Rodgers as a high-end handcuff if nothing else. Just don't expect him to tote the rock 30 times again.

Wendell Smallwood (RB, PHI) 8% owned - Smallwood is still running second to Ryan Mathews in Philadelphia, but we know Mathews' history. Smallwood showed his explosiveness with a 86-yard kickoff return TD, so leagues that count special teams stats should pay special attention. Smallwood is just a speculative adds for teams that have roster space at the moment, but could turn into an important waiver add if (when) Mathews is unavailable again.

Honorable Mentions: Dwayne Washington (RB, DET) 13% owned, Bilal Powell (RB, NYJ) 35% owned,  Matt Asiata (RB, MIN) 16% owned, DeAndre Washington (RB, OAK) 45% owned

Dark Horses - Week 7 Running Backs Waiver Wire

This group consists of running backs who are strictly desperation plays. They could serve as a bye week fill-in, short-term injury replacement or weekly lottery ticket.

Kenneth Dixon (RB, BAL) 28% owned - Give Terrance West some credit. He is holding onto his starting job with three straight solid performances. Dixon has moved down from a possible committee candidate to a handcuff only. He only saw two carries in Week 6 after seeing three carries the previous game. Dixon isn't a must-hold in anything other than dynasty leagues unless West falters or gets injured.

Rob Kelley (RB, WAS) 1% owned - This undrafted rookie is starting to work his way into the mix for Washington. He made the most of his time against the Eagles, running for 59 yards on five rushing attempts. Matt Jones put up another excellent effort, so Kelley won't be pushing for the starting job any time soon. Keep Kelley in mind as a possible insurance policy for Jones.

Zach Zenner (RB, DET) 1% owned - You might be tempted to avoid the Lions' backfield altogether, which may not be the worst idea. Still, it's worth mentioning that Zenner ran for 58 yards in his first extended action of the season. Riddick and Washington may return soon, rendering Zenner useless, but he could have use as a goal-line back if forced into action again. As a bigger back, he won't catch many passes which limits his value.

Honorable Mentions: C.J. Spiller (RB, SEA) 6% owned, Alfred Morris (RB, DAL) 16% owned, Alex Collins (RB, SEA) 0% owned, Damien Williams (RB, MIA) 0% owned, Daniel Lasco (RB, NO) 0% owned

Also-Rans - Time To Say Goodbye

Jalen Richard (RB, OAK) 32% owned - Richard has not been able to carve out a bigger role in the offense, despite the absence of Latavius Murray the past two weeks. He produced a total of 13 yards against the Chiefs and hasn't done much since his surprise 75 yard run in Week 1. With Murray due back and the Raiders' running game a big question mark, you can move on from Richard.

Cameron Artis-Payne (RB, CAR) 31% owned - James Stewart is back and as good as ever. CAP finally had success last week against Tampa with 85 yards and two TD. This week, he was inactive. It's apparent that he holds no value to the Panthers or fantasy owners as long as J-Stew is healthy.

Justin Forsett (RB, DET) 33% owned - Hopefully you didn't spend your hard-earned waiver budget adding Forsett when you saw he would start for the Lions this week. Forsett managed just five yards on five carries and was out-snapped by Zach Zenner. This was a desperation move once Theo Riddick was ruled out. Now that the Dwayne Washington hype has died down, he could be reacquired for virtually nothing and possesses more upside.