He only has one year left, so even if he doesn't play it will be a decent salary dump for us, worked out for both teams. It's just unfortunate to see him fall so quickly.
Prust only has 1 year left as well, so not sure how it's a cap relief for next year. Unless you just meant for this year?
Honestly everyone involved in that trade was horrible. Hodgson was bought out and is now a 3rd line centre with NSH, Kassian is where he's at, and Prust is now a 4th line player.
The only reason we shouldn't have made that trade in the end is Cody Hodgson had good chemistry being a sheltered 3rd line centre on our team and we could have used that going into the playoffs for that year where Kassian didn't help us. That was the Daniel Sedin injury year. If we would have gotten enough production from other lines (Kesler was useless that year) then we may have gotten past the LAK where Daniel Sedin would have been back and ready (he came back for last 2 games but it was rushed and not enough).