From what I've read, even if he's traded it's the same dead money because of the way his contract is structured. It was a signing bonus, so once it's paid, it can't be paid by another team.
Huh, didn't realise he'd got a load of prorated bonus hitting their cap. I stand corrected then, you're right - seems unlikely they trade him if they still have to eat the cap space. Although that presumably means he costs his new team comparatively little in wages, so maybe he becomes more interesting to a team with little cap space that's close to contending, and willing to give up a first round pick to get him as a difference maker.
Or the Raiders, because they could do literally anything for reasons that no one actually understands.
