You're smarter than that. Currently, the New England Patriots only have two cornerbacks under contract for the 2013 NFL Season: Dennard and Dowling. Are you seriously relying on Dowling to provide meaningful snaps next season?
As for free agency, I fully understand that the New England Patriots may explore that venue. However, in this aerial circus age, a NFL franchise needs five cornerbacks on the roster. I seriously doubt the New England Patriots would expend salary cap dollars in unrestricted free agency for the four other cornerbacks.
The statement that you are quoting was referring more to the safeties specifically. We may pursue the avenue of going after a proven vet who can step in immediately, which would instantly give us a much better safety grouping right off the bat, and would not necessarily be out of the price range like many other positions.
The CB position is entirely different due to the fact that we should sign at least ONE of Talib/Arrington, which instantly gives us 3 (and McCourty as a 4th depending upon what they want to do at the position of safety, as there are options). If you're saying that we'll likely draft a CB, I would certainly agree with you, but it very well may be explored via FA also. I have no idea where you are getting "4 other CB's" from?
As far as Dowling goes, he's still on the roster and he's still a high pick with potential. We have no idea if he can play or be dependable, so no we shouldn't "count on him." We also should not forget about him either, as he will once again be in the mix for a spot. It would help if he could stay healthy.
SAFETIES
1.McCourty
2. (W.Moore, Byrd, Delmas, Reed, Phillips, Hope, Clements, Crocker, Quin, Demps, Harris, L.Landry, Goldson, McBath, Bell, Clemons, Mundy, Jackson, Williams)---all free agents possibilities at a position that is affordable, is in need, and has been explored in the past couple/few seasons this way
3.Wilson
4.Gregory
5. Still leaves room for either a draft pick or other depth moves via the usual options
CORNERS
1. Dennard
2. Dowling
3. Probable retainment of ONE of either Talib/Arrington
4. (Grimes, S.Smith, Porter, Cason, Jammer, M.Trufant, C.Houston, DRC, Jenkins, S.Brown, K.Lewis, C.Williams, R.Mathis, Powers, Cox, Coe, Witherspoon, C.Griffen, Mouton)--all free agent possibilities
5. Still leaves room for a draft pick or other depth moves via the usual options