In terms of Boston deals, I think we have to wait until mid-season to let some of their recent acquisitions, player development, and injuries play out and for some Nats players to establish / firm up value.
On their end, they could give Yoshida at bats for a while against righties, especially if they move Duran to the Astros in a Paredes deal. Were there a deal for Paredes, then I could see a bit of a squeeze in the infield, so maybe a Durbin becomes available as a 2B (or IKF gets dumped for salary space). Yoshida probably needs to be dumped no later than when Casas comes back. They will give Casas a run at DH.
On our end, I've thought a Ruiz for Yoshida swap make sense because the total payment streams are comparable with Ruiz's having a substantially lower CBT hit because it is stretched out for 5 years instead of 2. If playing him at the start of the year while Ford plays AAA lets Ruiz show he's passable as a backup catcher then maybe that's some value to the Red Sox on top of the CBT implications (they could simply cut Keibert instead and still get the CBT benefit). I also think that Young may have a bit of value to the Sox if he shows he can hit well enough as a short-side of a platoon player. He might be the only cheap acquisition out there that could give almost as much defensive value as Rafaela, which would give the Sox some flexibility again with Rafaela. Of course, no Paredes, the CJ to second base also becomes attractive to them, while we could perhaps get Durbin back in the package. Durbin would be valuable here as an infield piece.