According to Joe Reedy with the Cincinnati Enquirer, "negotiations toward an extension with (Bengals safety Reggie) Nelson have been quiet." Considering that the team used the franchise tag on place-kicker Mike Nugent on Friday, this most certainty means that the team's starting free safety will hit the free agent market on March 13.
Nelson, who finished last season having his best season in his career by far, joined Cincinnati via a trade in 2010 sending cornerback David Jones to the Jacksonville Jaguars. How much did Jaguars fans dislike Nelson? They were actually happy to receive Jones, who was a mediocre at best defensive back with the Bengals.
That being said Nelson was a huge contributor on Cincinnati's seventh-ranked defense last year.
As for the reason that talks haven't taken place yet we can only suspect. Our most logical conclusion is that the Bengals are allowing him to hit free agency to see what offers exist, giving the Bengals a baseline from which to outbid other teams without significantly over-valuing the safety by preventing him from hitting the market before March 13.