He's a CB on the back 9 of his career. Happens to the best of them. Darrelle Revis, Joe Haden, Nnamdi, Charles Woodson, everyone declines. To be a truly great man to man CB you need to have that quick twitch and the athleticism to stay with WR's. Vontae has always been exposed by smaller, more sudden route runners (Antonio Brown torches us on a regular basis, Doug Baldwin the same). Vontae for a couple of years there was a top 5, arguably top 3 CB in the league. He is not that now.
Also got to give it to Doug Baldwin that he is a great route runner.
If Quincy comes back healthy and continues to flash, Melvin keeps up the solid play and Hairston continues to impress, I can see Vontae being the odd (and expensive) man out come the offseason when his contract is up. But with the 3 previously mentioned, Hooker and Farley as our safety pair and the prospect of Geathers maybe returning? The future of this secondary is very bright indeed.