I'd hold out for a bit to see what else you get offered. Thompson has been insanely efficient so far; I have a hard time seeing that continuing for the season (especially, from a fantasy production point of view, in a non-PPR).
I'd expect the other GMs to come at you hard over the next few days. See what the other dance partners look like before you choose one. I'd rather kick the tires on guys like Mixon, Carson, Lynch, Ajayi, Martin, etc. I doubt any of those guys are fully valued right now - and Ajayi, Mixon and Lynch owners might be getting jumpy.
Also, if they're not owned already, I'd look to pick up guys like Collins, Foreman and McGuire. You might take a hit for a few weeks, but all of those guys could emerge as leading their back fields in short order and shouldn't be PPR dependent.
At the very least, let that game tomorrow night play out. Not a great matchup for WAS, and the last thing you need is to trade for a player who winds up injured before he ever hits your roster.