In Franchise mode off-season, after you re-sign your players save the 
game. Enter Free Agent mode. If you do not like the free agents available 
(for example, if you need a top wide receiver and there are none), reload 
the game until you like the players that are available. You can also do 
this to make your division easier. For example, if you are the Jets and 
Randy Moss goes from the Patriots to the Rams then you do not have to 
worry about facing a player like that twice a season.