Aside from the obvious (Rogers), there are some interesting names here. Jefferson (drafted in the 3rd round in 02) played quite well and showed promise for the Colts, unfortunately he has had a whole host of injuries and I dont believe he has made it through a season without missing time. He has good size and can play both corner and safety. If they lose patience with someone like Lehan, and Jefferson can manage to pass a physical, he'd be a worthwhile pickup.
As for Marshall and Thorpe, they're both good athletes who should still qualify for the practice squad, and i'd imagine thats what they're being evaluated for. Marshall was obviously the starting QB at West Virginia, he lined up at WR for the 49ers and returned kicks (although he put up pretty lousy numbers doing so). He has experience at corner and safety too, and could be viewed as a project there. Thorpe has good speed and was on the KC practice squad last year. Thorpe went in the 4th round last year, Marshall in the 5th.