Help improve my roster!

Here is my current IDP roster: (10-team league)

LB: London Fletcher
LB: Stephen Tulloch
LB: Chad Greenway
DB: Yeremiah Bell
DB: Donte Whitner
DB: Kam Chancellor
DL: Justin Smith
DL: Mathias Kiwanuka
DL: Jason Pierre-Paul
Bench: B. Pollard

Here are some notable FA's available:
Cassius Vaughn
Shaun Smith
Bryan McCann
Eric Smith
Cary Williams
Chris Crocker
Kroy Biermann
Ryan Kerrigan
Juqua Parker
Chris Houston
Jason McCourty

I appreciate any help! I'm still somewhat new to IDP.