Your poll does not allow for multiple choices.
Here's my list in order of likelihood of making the opening day roster:
Harris: We should await further evidence as to whether he's capable of 20 carries. My sense is he'd be a nice component in another "TB by committee" season; more than that remains to be proven.
Green: He'll get another season to prove up. 2013 will be his second season off the ACL, the team has invested a 3rd. round pick and some time and effort, he's young, he's cheap and MM likes the guy. He'll be given every chance to earn the starting job, which in my opinion hinges on whether he can get yards after contact. Was it the knee, or is he an inherently soft runner? Personally, I don't expect more out of him than a passing down back.
Draft/FA: I'd guess we'll draft a runner, not another 3rd. down back, to compete for at least committee membership. I have a hard time seeing this happening above the 3rd. round. I wouldn't rule out an FA pickup, but no headline-making deal at the TB position.
Starks: He's under contract and he's cheap, so expect him in camp. In the end, you have to be worried about durability. It is very hard to let somebody else go when you have no confidence the guy you keep will be able to strap it on. I think he'll have to be 100% healthy through preseason, and have other guys fall flat, to make it to opening day.
Benson: He's 30 years old and coming off a fairly serious foot injury. He showed some flashes, but if we're to be honest on balance he looked "good" only in comparison to what we getting out of everybody else at the time. We were able to sign him for the minimum with no guarantee last season; I can't imagine that couldn't be repeated since his value in FA will be non-existent. If he doesn't make it past cut downs, it costs us nothing, and he'd be thankful for the opportunity. In the end, like Starks, it would take injuries or other options falling flat for him to make the opening day roster.
Saine: He's another 3rd. down back who doesn't get yards after contact. The Packers have more invested in Green. I don't know if he qualifies for a 3rd. year on PS; I think that's the best you can expect from him.
Grant: It's hard to see him coming back, even to camp.