Some of you are conflating paycut and restructuring which are not the same thing. He can restructure his deal to help the Saints be cap compliant and have room to sign FAs and still get every penny owed to him without taking 1 red cent of a pay cut.
He has no choice but to allow a simple restructure where salary is turned into a bonus. It's written into his contract that the Saints can do it at their will.
But that's not what Underhill was talking about. He's talking about an actual pay cut or some other form of restructure.