Brett has no say. He can force the Packers to place him back on the roster, but he has no leverage to force a release. He can ask for a trade, but he doesn't have any say in where he is traded. If he comes back and is placed on the roster, he could be a malcontent if he isn't starting, but that's about all the leverage he has. If he announces he wants to come back, but refuses to show for training camp, etc if he isn't released, the Packers would then have a reason to suspend him which would then be the same as if he stayed retired. It's a messy situation, but I don't blame the Packers for calling his bluff. What they are doing is exactly how they should handle it. My guess is their hope is Favre decides it isn't worth it and decides to stay retired.