That is correct, WC. The selling team must pay all guarantees that are already triggered in the contract, no matter if the player is on another team.
I will say, I might have spoken too fast about the possibility of trading Murray in-season. I have been saying in some posts that he would be worth a first-round pick. I still think he might, but I am retracting a little bit. The reason is that a buying team will only have about 8 games to determine if Murray is worth paying a lot in cash in 2027, and if not, they will get a pretty big cap hit from releasing him. It is not really a problem with salary cap-implications, but it is still a thing. Do a new team want to deal with that?
The more likely scenario is that the Cardinals sell him after this season. If they do it after the new league year starts, as you mentioned, they will be on the hook for his guaranteed salary in 2027, but it is only 19.5 mllions – so less than Justin Fields earn, for example – and if they have a new guy on a rookie contract, the overall cost would still be significantly less than this year. If it happens this way, a new team will owe Murray 0 dollars, and if they cut him after the 2026-season, they will get a minimal dead money-cap hit.
Another possibility for the Cardinals is that they can simply cut him after this season and get away with only taking on the dead money-hit with very little issues. It would actually save them cash.