Per Miguel's cap website, the Patriots have around $6 million in cap space for next season.
The free agents include:
RB LeGarrette Blount
WR Julian Edelman
TE Michael Hoomanawanui
C Ryan Wendell
LB Brandon Spikes
CB Aqib Talib
With Spikes not returning, Talib jumps to the top of the list of priorities for signing (if he wasn't already there). Of these players, you could likely rank their returns as:
1. Talib; 2. Edelman; 3. Wendell; 4. Blount; 5. Hoomanawanui
However, the Patriots likely won't be able to sign these players and take advantage of free agency with only $6mm.
DT Isaac Sopoaga ($2.01mm in cap savings)
OG Dan Connolly ($4.08mm cap hit/$2.51mm savings if cut)
SS Steve Gregory ($3.18mm/$1.86mm)
DT Tommy Kelly ($2.66mm/$1.74mm)
SS Adrian Wilson ($1.83mm/$671k)
DT Vince Wilfork (2014 is the final season of contract, $11.6mm cap hit/$7.5mm savings if cut)
K Stephen Gostkowski (final season, $3.80mm/$2.51mm)
Through some cap massaging, the Patriots should have plenty to bring back Talib on a $7-8mm/year contract (would place him around the 12-14th highest paid corner in the league and would likely be linked to health) and Edelman on a $6mm/year contract (probably with escalating deals).
What gets tricky is that the Patriots have plenty of key players becoming free agents after the 2014 season:
OT Marcus Cannon
OT Nate Solder (had a 5th season option)
OG Dan Connolly
RB Stevan Ridley
RB Shane Vereen
K Stephen Gostkowski
LS Danny Aiken
ST Matthew Slater
DT Tommy Kelly
DT Vince Wilfork
FS Devin McCourty
SS Steve Gregory
Add in quarterback Ryan Mallett and you have a full house that needs to be taken care of.
Of course, per Miguel, the Patriots should have roughly $30mm of cap space at that point (due to the expiring contracts of Connolly, Gostkowski, and Wilfork) and should be able to bring back some players. Still, with McCourty as the best free safety in the game, the Patriots should try to extend him sooner, rather than later.
There's lots to do this off-season, but the impending separation of the Patriots and Spikes just made things slightly more easy to manage.