Receivers: I really don't see any of these guys putting up top ten numbers, but...
After a slow start, Alshon Jeffery is having a great camp/preseason. He's likely the starter and should be a big red zone threat, especially next to Brandon Marshall who has consistently under-performed near the goalline. Almost no chance he gets 1,500 yards (like Cruz) in the Bears offense, but I wouldn't be surprised if he logs 8-10 touchdowns this season, which very well would make him fantasy relevant.
Streater from Oakland has been setting the world on fire in camp, but opportunities are going to be too slim to roster him. Not to mention I don't see him passing Heyward-Bey or Moore on the depth chart, but he's someone to keep an eye on.
Chris Hogan: if you watch Hard Knocks, you'll see plenty of footage of Hogan looking very good. He's earned the nickname from Reggie Bush "7-11 because he's always open." The coaches talk about it. The QBs talk about it... He doesn't exactly have world beaters in front of him, so keep an eye on this kid. (Roberto Wallace is another dark horse to emerge.)
Runningbacks: here's a few I'm drafting much higher than their ADP:
Rashad Jennings has had a great camp running with the starters and has looked very good in the preseason. New offense in Jax will slow down MJD's immediate involvement if/when he signs. Some respectable NFL/FF people think the MJD holdout is very serious and project that MJD misses at least a game or two. And if you consider holdouts to be an increased injury risk, Jennings may be THE back to grab after the first few rounds.
Gerhart is another rising backup. Don't know how he's looked in camp, but he was very successful last year when given the opportunity. He actually had a higher YPC than Peterson last year and Profootballfocus has been pimping Gerhart's vision and agility for a while. If Peterson suffers a setback or is reinjured, Gerhart should put up very good RB numbers.
Shane Vereen. I like his chances for getting the majority of touches in the NE backfield. If I can grab a guy in the late rounds that I end up starting a few times, I'm happy. To me, Vereen seems to be that one RB that can be had super late who still has a shot at starting and doesn't need injuries to find the playing field.