You make a good point about if they lose their OC, if he lands on a team in need of a QB.
I am not aware of Cassle saying that he would be content sitting on the bench behind Brady if he was offered a starter postion somewhere else. If that is the context that statement was made in, I would have serious concerns about him making it as a starter anywhere he goes or stays at.
As far as it being the Patriots way of doing buiness. I agree that owners need to be delicate on how they handle players contracts. No players are going to be easily signed or negotiated with if they feel an organaztion has a reputation for playing hardball tactics at a players expense. I think the general attitudes of the fan base have to be accounted for as well.
Let me state it like this:
Given between two choices the first being a Tom Brady lead team struggling to get into the post season and not really making of a splash once getting in there or a Cassle lead offense that continues to keep the Patriots competive deep into the post season, I think the fans would prefer the latter of the two.
If you believe the Patriots have enough resources without trading Brady to remain a dominant force in the nfl then fine keep him, but if you think they need extra help because of aging talent at various postions to remain dominant, then I think you have to consider making that tough decission of getting some value out of a brady Trade not to mention opening up some more cap space.
Look at the 49er's when they got rid of Montanna, Young was not exactly welcomly recieved but in the end he did bring them rings. I'm not saying Cassel is a better QB then Brady, but Brady is not winning games by himself. He is very good at his role but he is a role player in a system and if that system can keep enough talent in enough of the roles then they can continue to dominate for years to come depending on who they pick up with the extra picks they get.
If Cassel is a one hit wonder then obviously it would be a huge mistake to let brady go but if he turns out to be the real deal. It good be a smart decission that will leave them secure at the qb for another decade.
Bottom line, regardless of what Cassel has said in the past if he continues to light up the score board he will be a starter next season on some team, somewhere.