There is no official word yet, but it's not hard to speculate. He was being paid ~6 mil per year (5yrs - 29mil), based on his career-high year in tackles, inflated sense of self-worth, and recent posturing, does it really sound like he is willing to take a pay cut?
The Bills are not creating a hole by losing Whitner, in fact it will probably feel like an anchor has been removed from the neck of OBD. Of course fans will scream that the team keeps wasting 1st round picks, and they're right, but it's not news.