Stanton was healthy almost all of last year and carried the offense for much of the season. Not sure what to say about 2019. I still think he'll be productive in the 2nd half. And i think the Marlins are eating a portion of his contact too.
Whereas Sandoval and Rusty are being paid richly by the Sox to stay far away from Fenway, thus prohibiting your team from getting the bullpen help it needs, or as you said, crippling it.