Every year NFL executives make tons of decisions to reshape their teams in free agency. They allow popular players and fan favorites to walk away -- sometimes to division rivals (LB David Thornton going from the Colts to the Titans) or to serious competitors (K Adam Vinatieri leaving the Patriots for the Colts). Other times, teams believe that they have a young player waiting in the wings to replace a fixture whose contract is up (New Orleans DE Will Smith taking over for the departed Darren Howard, who is now with the Eagles), so they can use those funds to help their team in other areas.
Many players will go back to an old team (Philadelphia's Shawn Barber) or many coaches and general managers will bring in players who they trust from past winning relationships (Willie McGinest going from the Patriots to the Browns). Teams with a recent history of losing (Tennessee) will overspend a bit to bring in players from winning organizations to infuse a healthier perspective to their locker room.
This offseason, perennial powerhouses New England and Indianapolis took steps backward, while up-and-coming teams Arizona and Cleveland made strides toward building a winner. This is the beauty of the NFL offseason -- it brings hope. Ask Kansas City Royals and Pittsburgh Pirates fans if they would be interested in such a system in Major League Baseball that would restore their teams somewhere close to respectability instead of being the farm system for the St. Louis Cardinals, Boston Red Sox and New York Yankees year after year.