Antoine Winfield is the NFL's most underrated free agent. Sure the guy is aging but he had 101 tackles last year because he is simply the BEST corner in football against the run. He isn't a lockdown corner like Revis or Sherman but his coverage skill are still honed for excellence. The man didn't allow one TD through the air last season, that's nothing short of impressive. Most shockingly, Pro Football Focus rated Winfield as the BEST all around corner in the NFL last year.
Check it out for yourselves: https://www.profootballfocus.com/blog/2013/03/28/antoine-winfield-pffs-no-1-cornerback/