Chaney (healthy) should be taken with a boulder of salt. I'm not ready to say I liked this kid better when his name was Robert Burns, but it's getting close. It's time to show you can produce at this level. Like, right now. The cliche "The best ability is availability" is as true as it gets. So Chaney (healthy), sure, he should be very good for us. But he hasn't been (healthy) in about 4 years now. So I'll believe that when I see it.
Knighton is absolutely not a Top 2 back when you use it in the traditional sense. Check the tweet/graphs I showed above. He's been absolutely terrible as a traditional RB. His best role is as a 3rd down back/slot WR/being motioned out into space in 2-back sets, etc. Line him up as a single back and run him off tackle? No thanks. He's been unusable in that role. BUT HE CAN BE EXCELLENT IF YOU USE HIM CORRECTLY!
Henry Parrish is my pick for the most productive back as it stands right now. Chaney's health, Rooster's overall ability as a traditional back, and Thad's lack of explosion opens the door for Parrish. He does everything well, even if he's not exceptional with any singular attribute. I think he helps us a TON this year.
And the wildcard is Citizen. I don't like to rely on true freshmen backs unless they're Duke Johnson. I'm not saying he won't help or have a role or be very good, I just don't think you can go into the season expecting him to be your workhorse back. But IMO, if we assume Chaney is fully healthy, he is 1A, Parrish is 1B, Citizen is sprinkled in and Rooster is used exclusively in the pass game. If Chaney gets hurt again, Parrish and Thad are your co-lead dogs, Citizen gets an uptick, and Rooster needs to stay in his role as being used exclusively on 3rd down, hurry up, 2 minute, etc.