Trades? In the NFL? The insanity of it!

A couple of big names in Brandon Marshall and LeSean McCoy moving this offseason. Smaller name in Cassel, but that could still likely a move for a starting QB. Not something you often see in the NFL. Teams are reluctant to part with draft picks, so usually players who have worn out their welcome, even if they are still a certainty to play in the NFL, end up being released instead of traded. Also, the structure of the salary cap means that trading a player with years left on his contract results in money accelerated against your cap.

So what's the difference this year? Why the change? Is this just a new owner in Buffalo going crazy, is was there subtle change that makes this approach viable?