I don't know that I see a lot of battles for roster spots but there are some position groups I'm going to pay some extra attention to.
First off, I think QB, RB, TE, CB, S are pretty well set, with nothing more than maybe some tweaking of roles.
I also think the starting OL is set as well as the top 3 backups in Tretter, Spriggs and Murphy. If they go with 9, it'll be Rotterham, Taylor and Barclay battling for the 9th spot, but not much drama other than that. I will be watching the second group closely in pre-season to see if we finally have some high quality back-ups who can transition into starters in a year or two. I haven't seen those kind of backups in a few years.
I don't see much of a battle at DL. Clark, Lowry, Guion, Daniels are sure bets. Ringo seems likely especially to start the season, with Pennel starting the year suspended. Jones can move some between the elephant LB role and DE so adds some versatility. Price, the kid from Tex-SA seems like a good bet for the PS.
WR will be interesting. I still think they could keep 6 but history says they probably won't. Abby would seem like the odd man out. Also, do they continue to use Adams on the outside when they go with 3 WRs or might we see more of Janis in that role. Monty seems more of a slot guy when they go 4-wide and Davis is a rookie and probably will need some time to earn snaps. After that I only see PS guys.
At OLB it looks like it will be Peppers and CM3 starting outside, with Perry, Elliot and Jones providing most of the rotation snaps. Fackrell has some skills and might push Elliot for snaps and maybe even a roster spot, though I think they will keep all 6 of these guys.
ILB should be the most interesting position. Ryan is likely to improve on his rookie year. Martinez brings a little hype with him and might get the nod ahead of Barrington. After that, who knows. McCray seems highly likely to make the 53 but I don't know if his role is inside or outside since I think he played some of each for Denver. The numbers suggest inside since they already have a lot of bodies outside. Thomas did OK as the dime guy but isn't a starting quality guy and might be a numbers casualty. Brown and Pikula are a couple of rookies who might get a shot to make the 53 and if not one likely makes the PS. I suspect this is the end of the line for Bradford. If this group falters, we may well see CM3 taking snaps in the middle again. To me this is the most interesting position battle because both starting spots are really up for grabs between Ryan, Barrington, Martinez and McCray.