Teams don't usually trade pass rushers even if they're 0-8 and season is over. Like OT and CB, it's a premium position. Guess it could happen but not sure there's a history of it in the NFL.
I would love to see Thomas here. I'd trade Seattle a 2nd and give him a top 5 contract then let Dix walk after the season. Dix has seriously regressed since his 2016 season.