Regardless the root or secondary causes, veteran players in the 7+ years experience range do seem to be viewed more unfavorably than ever before by NFL teams.
Sometimes the sequence of events is almost unbelievable. Last June John Abraham signed a 3-year, $17 million contract with the Falcons and less than a year later he was released, after leading the team in sacks with 10.
I'm not quite sure what's going on here but there's definitely something affecting the market. I think part of it is the flatness of the cap due to the new CBA.