The Pats currently have 55 players under contract going into free agency. That means a minimum of 25 players added to get to the pre-season max of 80. That's a lot of players.
This tells me that the Pats will be active in Free Agency as well as with UDFAs. I wouldn't be surprised to see at least 15 UDFAs signed by the Pats this year.
I don't quite follow the "active in Free Agency" part unless you mean signing a bunch of JAGs being "active". Doesn't it really depend on WHICH 55 players we are talking about? There are only 46 gameday actives. Of the 55 under contract, I can see the following (pending health/salary dump) always being part of that active group:
QB Brady, Mallett
RB Ridley, Vereen, Demps
TE Gronk, Hernandez, Ballard
OL Solder, Mankins, Connolly, Wendell, Cannon
DL Wilfork, Armstead, Jones, Ninkovich
LB Mayo, Spikes, Hightower, Fletcher
DB McCourty, Dennard, Gregory, Wilson
ST Gostkowski, Mesko, Aiken, Slater, Ebner
That is 30 players of the 46 with almost all starters intact. Now add the questionable injury/salary/position battle guys:
WR Lloyd
CB Dowling
DT 2 of Pryor/Love/Deaderick
That puts a realistic gameday active number at 34 of 46. A number of the remaining 12 will go to developmental guys that have niche skills, have high upside and/or form the core of ST:
RB Bolden
OL Zusevics
DT Francis, Bequette
LB Tarpinian
There could be as few as 7 active spots "open" (not considering upgrades) and really only 2 or 3 are starters (WR, OT and CB).
I see the Pats spending a bunch of the available cap space on these 3 positions, adding some 2nd tier vets to compete elsewhere (dating, not marriage) and drafting BPA into the strength of this draft...particularly at DB.