From what I understand (and if I'm wrong, correct me), a big point of negotiation is *when* the signing bonus gets paid.
So, if they agree to pay the signing bonus upfront, and then Zach gets traded after year one, the new team won't have to pay the signing bonus. Is that right? On the other hand, if they agree to spread it out over four years, and Zach gets traded after year one, then the new team would have to pay the three remaining installments. Is that right? Or would the Jets still be on the hook for all of the signing bonus?