The Pats could franchise him and not sign him right away as the negotiate a longer deal. It almost never happens that a player signs right away for the one year as their agents are doing a huge disservice to their client long if they take that deal. Cassel's agent will be looking for a huge up front bonus plus years for long term security. The chances of Cassel taking the franchise offer right away is extremely slim as it will be pretty obvious to the agent what the Pats are doing and wouldn't want to screw up his client's relationship with the Pats.
this is true, but the act of franchising a player is offering a franchise contract. So as mentioned, if he and his agent realize they might have trouble getting 15 million guaranteed they may sign. While I agree it wouldnt be a great strategy, you could foresee a situation where he signs, gets 15 mill guaranteed to sit on the bench, then goes back to being a FA next year (it isnt like his skills will have diminished). I am not advocating this, but it is a real risk for the Pats.
What I see as a much more likely scenario is the agent sees what the Pats are doing, waits for the trade to happen and then negotiates a deal that would be similar to Aaron Rodgers(who happens to have the same agent as Cassel) where Cassel would get a $20-25 million signing bonus, a $10-15 million 2009 salary and then incrementally smaller but increasing amounts thereafter.
That pays Cassel somewhere between $30-40 million next year and playing as opposed to $14 million and sitting.
No come on, how likely is your scenario of him taking the franchise tag right away? Almost none.