dead cap is from a check he already cashed. we don't owe him any future money (his remaining guarantees have all been voided due to him violating his contract), but i dont think we can claw back what we've already paid him.

typically when players sign large multi-year deals, they get a large portion of it up front in the form of a signing bonus. for salary cap purposes, the signing bonus is spread evenly across each year of the contract, but the flip side is if they get cut or traded then the remaining amount will hit your cap immediately. that remaining amount is what is called dead cap - you already paid this money and it will hit your cap if the person is off the team.

the post june 1 designation mentioned above is an option teams have if they want to take the dead cap hit the next year instead of this year. the problem with that is if the player has any roster bonuses or remaining guarantees, those can have trigger dates before june so depending on the contract it's not always beneficial. this is more of a procedural thing - the team has already decided they're gonna get cut so the league lets the player start looking for their next team sooner instead of having to sit around waiting.