My thoughts on the position players.
Has to go
The only player who "has to go" is Cespedes. There is no place for him and he definitely has more value playing every day on another team than he does riding the pine in Boston.
Probably better off somewhere else - Higher paid vets Vic and Craig
Vic - When healthy, he can play all 3 spots. He's great insurance. But if you're up against a budget and you need to clear space to make room for pitching help then maybe he's better off elsewhere.
Craig - Depends what you can get and what you think the odds are he can bounce back and build value. Hard to see him having a role to even build that value given existing depth. It's not unprecedented though...see Carp, Mike.
Better off keeping them
Napoli - Not sure why you'd trade his bat to clear salary assuming you can move Vic or Craig
Holt - I'd like to keep him as super utility man, particularly if Vic is traded. If someone else loves him then he is worth more somewhere else...I'm assuming that most teams think he's best utilized as a super utility guy on a top team instead of a starter on a bad team.
Rebuild value/wait and see or trade them now?
WMB - I would trade now. Doesn't have much of a role anymore, particularly if they keep Holt. It's a matter of if you think he can regain value in AAA. I don't think he will and I want Cecchini taking ABs and reps at 3B.
JBJ - I'd rather wait and see. A great defensive replacement but he should be getting every day at bats. Pawtucket seems like a good choice for him and Red Sox so he can be 4th OF in the event of an injury. Long term it's unlikely there's a role for him but it could happen if he really turns it around in AAA (see below).
Cecchini - Wait and see. I think he finds his stroke and improves his stock. Like JBJ he's likely to be more valuable to another team once he regains some trade value but there's a chance (edit
he proves he should be in Boston (/edit) or that the roster shakes out such that he's worth keeping around.
Do not trade - X and Betts
The only players who absolutely should not go are X and Betts (unless they receive a similarly talented player very early in his career). Betts and X are the guys who make the math work. You don't want to pay every man on your roster 8 figures into his 30's. These are the guys you bet on, no pun intended.
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I really don't think there's that much of a log jam. Rather, I think they are being proactive on two fronts.
-The first is preventing a problem should Ortiz (or Napoli) finally succumb to age. Without these moves the entire offense hinges on Ortiz staying healthy.
-The second is relying on a JBJ type of player to step in right away and hold down a spot only to have him be one of the worst every day players in MLB. Marrero could have found himself in a JBJ similar situation. Now there's going to be no desire to rush him. You could argue Castillo is in the same boat but at $70M we all f'ing hope not.
In terms of sorting it all out, I think it will take care of itself.
-Ortiz and Napoli are only signed for 2 more years and are long in the tooth. Panda and Hanley can occupy those two spots if need be. (This is why I'd wait and see on Cecchini, too.)
-X can try his hand at SS for the next two seasons. If it doesn't work then he can move to 3B. If Marrero proves he needs to be starting in Boston then this is the same answer.