unless i'm misunderstanding, the only difference is you get a year of play for 15 plus 20m next year cap hit vs just the 20 m cap hit
The way Reddick's contract is set up, he currently has 3 void years attached to the end of his deal (which ends this season). If his contract isn't extended prior to him hitting free agency, then the protated money in those 3 years gets accelerated to next years cap as dead money (in the amount of ~ $15 mil). His cap value this season if he's on the team is ~ $22 mil.
So if he plays this year and doesn't get a contract extension, he has a cap value of $22 mil this year, for playing for us, and then next year we have to account $15 mil of dead money while he plays somewhere else.
If we cut or trade him this year, then we incur ~ $20.5 mil of dead money this year, all while he plays elsewhere. But then he's off the books next year.
If we were in a rebuilding mode, sure trade him and get what you can get back and then he's off the books for next season.
But since we're not in a rebuilding mode and Howie clearly thinks this team can compete for a superbowl this year, it makes no sense to have $20 mil of dead cap on the books this year for a guy who isn't playing for you who oh yeah also happens to be the best DE/OLB on the team.
I'm sure the Eagles have offered him a contract extension, but he's trying to see if he can get better elsewhere.