Im not even sure what "not negotiating with the Patriots" means. Doesn't seem like to me that the NFL has ever done this.
As far as legal action, I think it is tricky and will take a long time, the guys in the bountygate deal were required to go to arbitration first, that meant Goody was the arbitrator, only after that they went to a federal judge and forced the NFL to use an outside arbitrator. Goodell is Brady's first shot at it and Goodell isnt going to change it. Thats how this goes if it indeed goes that way at all.
Im not even sure of my confidence of Brady fighting any penalty, we all think he will but Im not so sure. Thats just my opinion.