The starting combination is either going to be Simpson + Green or Simpson + Caldwell. Green will eventually secure that spot, but I think the coaches will make that determination based on competition through practice. Either way, those 3 guys are the first off the bench.
Behind them Shipley is secure in his slot position. The guy is Mr. Dependable.
That leaves Cosby, Whalen, Hawkins and Russell. I've seen nothing of Russell that merits a spot of the 53-man roster. Hawkins has impressed as a kick returner and gunner but I'm not sure he can beat out Cosby for that gig full-time. Whalen has been quiet but I've never read anything negative about him.