Do you want to have pretty much any player in Madden games? Well you can, just keep reading.

[edit] Steps

Pick any player you want, just go to 'view roster' on the franchise mode and switch to the team that has the player you want. Then, press the x button to select the player.
Go to 'edit player info' and switch the position. You want to switch the players position to something the complete total opposite of its original position.
Accept everything. Then, go to 'view roster' to the team that has that player and trade for him. Usually the player will be a worse overall, but if it's not then keep switching positions until they get worse.
When you finally get the player on your team, switch the player's position to its original state.