I don't think Casey has a problem with being traded, I'm sure he understands that's the business part of it. I think he feels the way it was done, hearing about the trade just minutes before it happened. After 9 years he deserved better than that, and for a 7th rounder?
He feels disrespected and rightfully so, even though it's a business and his salary was greater than his production, there still needs to be room for decency, respect and professionalism.
A simple sit down with him I'm sure would have went a long way.