The Seahawks tried signing him in free agency last year, but he chose the Eagles. This time around, he didn't have a choice, he was traded.
I don't think the Seahawks would have wanted to take on his salary. Huff was a disappointment last year, but he was also injured. I hope he doesn't revert back to what he was in '23 (10 sacks, 21 QB hits). Bosa and Huff could be a tough pair to deal with.
My guess is that Vic Fangio knows what he's doing, and his assessment is that Huff isn't worth the money.