This is all barring trades:

Bold Italics means the Starter, Bold means a lock, Parentheses means not a lock, Just Italics means Rookie Free Agent.

Offense:

QB- Joe Flacco, John Beck, Troy Smith, Marc Bulger

RB- Ray Rice, Willis McGahee, (Jalen Parmale, Matt Lawrence, Curtis Steele)

FB- Le'Ron McClain, (Mike McLaughlin)

WR- Anquan Boldin, Derrick Mason, Donte Stallworth, (Mark Clayton, David Reed, Marcus Smith, Eron Riley, Demetrius Williams, Justin Harper)

TE- Todd Heap, Dennis Pitta, Ed Dickson, (Davon Drew)

OT- Michael Oher, Jared Gaither, Oniel Cousins, (Tony Moll, Stefan Rodgers, Ramon Harewood, Joe Reitz)

OG- Ben Grubbs, Marshal Yanda, Chris Chester

C- Matt Birk, David Hale

DE- Haloti Ngata, Cory Redding, Trevor Pryce, Paul Kruger, (Lamar Divens, Arthur Jones)

DT- Kelly Gregg, Terrence Cody, (Brandon McKinney, Kelly Talavou)

ILB- Ray Lewis, Dannell Ellerbe, Tavares Gooden, Brendon Ayanbadejo, (Jason Phillips, Prescott Burgess)

OLB- Jarret Johnson, Terrell Suggs, Sergio Kindle, Antwan Barnes, (Jameel McClain, Edgar Jones, Albert McClellan)

CB- Domonique Foxworth, Chris Carr, Ladarius Webb, Fabian Washington, (Travis Fisher, Walt Harris,  Cary Williams, Prince Miller)

S- Ed Reed, Dawan Landry, Haruki Nakamura, Tom Zbikowski, (KJ Gerard, Marcus Paschal, Ken Hamlin)

Special Teams:

K- Billy Cundiff or Shayne Graham

P- Sam Koch 

Long Snapper: Matt Katula or Morgan Cox 

Locks: 45 (Did not include Webb and Ed Reed, who will likely start on the PUP list)

Out of 80 players, there are 45 locks.  That means the remaining players are battling it out for 8 spots, although some players will make the practice squad.  I will only discuss the practice squad to discuss player who I think will for sure be on it to start the year, like Ramon Harewood.  Others, like Ladarius Webb, and likely Ed Reed will likely start on the PUP list opening up one additional spot.  

I will start out by addressing how many of the remaining spots will be filled at specific positions.  After the locks, we still have holes at CB, WR, FB, #3 RB, and need more depth on the O-line. So assuming McLaughlin makes it at FB, we keep 2/3 of the backup QB's, Hamlin instead of Reed, and a #3 RB, that leaves 7 spots for the remaining players.  We are left with:

6 SPOTS for 20 PLAYERS!

I guarantee that we will have teams bidding for many of our castoffs, albeit with late round draft picks.  Players like Antwan Barnes and Jameel McClain will likely garner much interest.  

20 players: WR: (Marcus Smith, Mark Clayton, Demetrius Williams, Justin Harper, David Reed, Eron Riley), DB: (Travis Fisher, Walt Harris, Cary Williams, Prince Miller, KJ Gerard), DL: (Brandon McKinney, Kelly Talavou, Lamar Divens, Arthur Jones) LB: (Edgar Jones, Jameel McClain,  Jason Phillips) Tony Moll, and Davon Drew .

So out of the remaining 6 spots, my guesses are we keep: 1 LB, 1 DL, 2 CB, 2 WR .  This leaves O-line, which I believe we need to carry one more player, but do not see the caliber of player at that position that would make this roster.  I fully expect us to trade from our WR and LB depth this pre-season in order to bolster our other positions and pick up some draft picks instead of losing players for nothing.  

1 LB: McClain (If we trade Barnes or McClain, then Phillips)

1 DL: Hoping for Arthur Jones, but McKinney, Divens and Talavou or valuable depth that other teams will want

2 CB: Likely one of the veterans (Fisher or Harris), and 1 youngster (hopefully Cary Williams, but could be Miller)

2 WR: Hopefully Clayton will be one of them, and I am rooting for David Reed.  I think we can stash Marcus Smith on the PS until someone gets injured.