I have resigned myself to the idea that Mookie isn't coming through that door in 2021. If you were a championship-type player, someone you build a team around, would you want to come back to a team that's obviously in the start of a rebuild, but with a decimated farm? I sure wouldn't. Trust me. After you've been on a winning team losing becomes not an option if you can control it. I'd be wiling to settle for a few million dollars less over the life of the contract to play for a winner. (And I know that "a few million dollars' is still a lot of money but it's not as much when you have 300 of them piled up anyway). So I don't see him coming back. In fact, IMO he'd be stupid if he does come back.
So then we have JBJ, who can be signed for a whole lot less to anchor that outfield. I don't expect to see anyone throwing $300M, $200M, or even $100M his way unless it's a lifetime contract - and the Sox would be stupid to offer anyone not named Mookie (or maybe Devers) a lifetime contract.
Like DD, I like defense! I believe that defense is as important to winning games as is offense and I believe our pitching staff would tell you the same thing. Like DD, I also believe in the old adage (if 'old adages' haven't been outdated in this time of metrics) of being Solid Up The Middle. Our up-the-middle defense is weak enough as it is with Bogaerts and a PTBNL in the infield. [sidebar disclaimer: IMO Bogaerts offensive capability outweighs his defensive shortcomings so I'm not advocating moving him but that doesn't make him any better defensively].
Getting back to SUTM now, I've always believed that a winning team should be solid defensively at C, 2b, SS, & CF and accept any offensive shortcomings at those positions to be that way. I've also believed that if a team has to have defensive weaknesses it should be at the corner positions. I don't particularly like having defensive weaknesses anywhere but if a team has an offensive player like XBo in an UTM position they can afford a weakness at a corner position.
In a nutshell, if the Sox are going into a rebuild mode I believe they should take the longer view and keep the best players they can afford to keep in the long run and not be so focused on the next year that they let one (or more) of those players get away. I also believe that one in the hand is worth two in the bush. We KNOW we can sign JBJ to another season and then deal with signing him (or not) for 2021 depending on what the 2021 team looks like. I'd rather do that and accept the salary consequences than risk our outfield defense in 2021 & beyond by losing both JBJ for 2020 & Mookie in 2021 in two years. I DO NOT want to see this team turn into Baltimore or Toronto for the sake of a 'rebuild'.
And BTW, I also haven't given up on the future of the team that takes the field now. Our only weakness is starting pitching and it's entirely possible that we, for some reason, hit The Perfect Storm of bad pitching this year. The thing that concerns me most is the situation with Sale, which, in spite of what I read here, hasn't been resolved yet and won't be until they can do more diagnostic work on his elbow. But even if Sale goes down in 2020 I still keep JBJ and try to sign him for 2021 and beyond.
Phew!