The more I think about it, the more I like the idea of a safe winter where they trade JBJ for Belt and a prospect or bench piece and then sign Jay Bruce to play left field. Yeah, he's more likely 2016 Jay Bruce than the 2017 version going forward, meaning about 10% better than league average, but the 30 HR power is real and Bruce and Belt would be an overall upgrade offensively over JBJ and Moreland. You are sacrificing defense in the outfield, but Benintendi can play a solid CF and Bruce should be pretty good in left. Bruce can also handle a little 1st base if need be, meaning no need to suffer Hanley out there.
You could reasonably expect that lineup to do the following with regard to home runs: Betts (20-25), Benintendi (20), Bruce (30), Belt (20), Pedroia/2B (10), Bogaerts (15), Devers (20), Vazquez (5), Hanley (20). I'm assuming Hyers will have a slight upward impact on a few of these guys and that Bogaerts will be one of the players he will focus on with approach. That's 160-165 HR from just the starters. Getting 40 or so from the bench isn't unreasonable, especially if Brentz is there. That gets them back to about league average and has consistent home run threats throughout most of the lineup. As a floor, this feels reasonable. If anyone outperforms expectations (like Devers), even better.
This also likely keeps them under the $237M secondary threshold with a little room to maneuver in season without costing them any picks for QO signees or IFA money. If they can keep Bruce on the hook for a bit while they wait out the Martinez market, this would be a fine fallback position, IMO.