Really appreciate the conversation going on in here. The Seahawks have found themselves really deep at RB this year, and it's going to suck letting some of them go. Wouldn't be surprised if any and all of the RBs we cut this preseason end up on other teams, there's a lot of talent here right now. Here's my take...
Lacy and Rawls are the safest of the bunch. Lacy has proven he's a competent and reliable #1 in an offense that didn't really care for running the ball much, other than to try and keep defenses more honest for Rodgers. Now he's with the Hawks who, ideally, want to run the ball more than any other team in the league. From what I've seen over Lacy's career, is that his body can hold up to the duty of the bell cow and we'll have multiple backs to rotate and keep his carries in-check. I know he hasn't been all that impressive in preseason, but he's coming back from an ankle sprain and I don't think he's been overly-laborious (no need to) with his playing time so far.
I think Rawls is safe because of (and it sucks to say) his flashes of brilliance in late 2015 and the potential he's continued to show between early last season and training camps. I say it sucks to say because at this point he's being protected mainly based off of production that was multiple seasons ago. Dude's a gamer, but IMO it's getting close to the Kearse situation (some of the biggest plays of our history, but seemingly past that type of production now). I don't want this conversation to go into our WR situation, but I feel like Rawls is being rewarded for previous play and not his current/recent production. This season is going to be a make-or-break for Rawls. If he proves he can be the #1 or stay healthy splitting carries with Lacy, he's got a great shot at a second contract with us. We know what he can do, he's just gotta prove he can be reliable in this league. I love the kid, rarely do you see someone so jacked up and excited about being where he is and working with the opportunities that he gets. He loves the game.
From here, I think the RB gets pretty chaotic and kind of in a good way. Prosise has proven he can be a huge mismatch and tilt the field. He's an explosive player that can hybrid between RB/WR, but he's still proving to be unavailable and unreliable. I want to see him on the field really bad, and I believe he could have played the last couple weeks if they decided to push him or the situation was different (like playoffs), but the coaches aren't going to push him because of his injury history, potential and what he showed in limited time last year. In a lot of ways Prosise is similar to the Harvin situation, but he's actually level-headed and not a doucher with attitude problems according to all accounts. Personally, I think he's one of the highest-risk/reward personnel decisions on the roster. Mostly because of who's behind him (or started the preseason behind him) on the depth chart.
Carson has been an absolute pleasure to watch this season. I was pretty impressed with his film from OSU last year and loved the physicality that he finished runs with. So far all he's done is make Pete and the rest of Seattle rant and rave about him. He's quick, decisive, runs with authority and so far has taken care of the football. I honestly have no idea where they plan on sticking Carson on the depth chart right now. He could be at the top, he could be #3 or lower (as of right now he's not even listed on the official depth chart). Either way, I think he's going to end up making this team barring any meltdowns in the final two weeks of preseason.
As ACFan has pointed out, Collins has been really reliable as a third down and short yardage back so far this preseason. The way I see it, and I want to love AC, he's kind of the floor as far as our RB group goes. He's consistent, proven he can stay healthy and transform his body (though his time with #1s and regular season has been limited), but ultimately average. He's Mr. Reliable. The way I see it, he brings about the exact same skills/value to the team as Lacy and I think they're all-in on giving Lacy a spot as the #1 or #2 no matter what happens this year. I just think between Lacy's contract and seemingly having a slightly higher ceiling, AC is going to end up cut this preseason. It would be the Seahawk way to watch him go to another team with better run-blocking and watch him post 4+ YPC all season.
While Davis has had flashes in preseason, I think he's on the outside looking in. There's just too much talent ahead of him and we're going to end up keeping Marcel Reece so that's another roster spot that'll be eaten up by a back that's basically a lock to make the squad. Though, we've cut and resigned FBs seemingly depending on the flavor of the week in the past.
The hardest part about this situation, in my eyes, has to be the risk/reward of Collin's reliability vs. Rawls/Prosise's talent. There's points to be made for all three of these players to make the squad, but surely we aren't going to keep all of them -- and we certainly won't be able to stash any of them on our practice squad. Going to be some tough decisions for our coaching staff over the next couple weeks.
TLDR; I think Lacy and Rawls are locks. Carson and Prosise have one foot in the door, while Collins and Davis are unfortunately on the outside looking in.