The CFL, NFL and arena league all honour each other's contracts. A player cannot walk away from his contract with one league to play in another. And the NFL loan was paid back a few years ago.
yup, he's right. If you sign a contract, you can't leave it. they'll suspend you.. but you can't play for someone else , NFL or not.
the only league that doesn't honour this is the KHL, where players leave the NHL with contracts to go play there..