Don't Call Up: Bradley Zimmer
Bradley Zimmer would definitely be a head turner if you were to bring him up from Triple-A towards the end of the year to push for the playoffs, but, at the end of the day, why waste a 40-man roster spot on an outfielder, and a left-handed hitting one at that (which you have plenty of already) when you could very well use it on a pitcher, if needed.
Instead of Zimmer, you could look at a pitcher like Nick Robertson who was acquired in the trade that sent Kike Hernandez to the Dodgers.
Maybe by that point Boston may need some help in the bullpen, or maybe even a short length starter because its bullpen is so solid, but either way Zimmer is not the way to go.
The right way to go for the Red Sox is to resign Zimmer after the offseason to a minor league deal and let him play his heart out in spring training and probably earn a spot on the roster that way as a back-up to Rafaela or maybe even Rob Refsnyder.
T-Minus 16 days until roster expansion, what Boston does, remains to be seen.