We can, but we currently have 5 CB and 5 Safeties (if you include Ebner), this would give us 11 total which is a lot, 6 CB, 5 S. Skinner has to be our bottom player but the roster would be mis-shapen with all those DBs and only 4 (Mayo, High, Collins, White) LB unless I missed one.
Unless I have missed a transaction, we have 6 safeties.
McCourty, Chung, Harmon, Wilson, Ebner and Jones
We will soon have 6 corners.
Revis, Browner, Ryan, Arrington, Dennard, and Butler
We have 5 LB's
Mayo, Hightower, Collins, Skinner and White
Of course, White doesn't play defense (ONE defensive rep all last year).
Clearly 12 is a lot of defensive backs.
BOTTOM LINE
I am somewhat surprised that Dennard has not been put on the IR-Return list already. I suppose that we can hope that he will return soon. In any case, it would seem that we will cut a defensive back when Browner is added, still giving us ELEVEN defensive backs as we have now.