Cooper is better than Hopkins, two years younger and cost us next to nothing on the cap.
Sounds like Tennessee is eating half of Hopkins prorated cap, which leaves about 2.6M the Chiefs have to take on, compared to 800K for Cooper.
Better player, younger player, 2M cheaper this year = a 3rd vs the 5th KC gave up.
It's also likely an audition for Cooper to get a 1-2 year extension with us, whereas Hopkins would be a straight rental. Not to say he won't re-sign with KC this off-season, but Hopkins is at the mercenary portion of his career. Cooper could still have a multi-year deal left in him if the money/fit is right.