Shaw is the perfect hit. Capable of batting leadoff and getting n base. 15-20 HR power. Speedy enough to stretch singles into doubles. Great defense. And probably not available for any package Boston will offer.
But even without Shaw, the Cubs are a perfect match, needing botj a closer and uninjured starting pitching. And they have several MLB-ready middle infield prospects and even a catcher that can hit, all of whom are blocked at the MLB level. (The catcher, Moises Ballesteros, does occasionally play DH for them.)
If Ballesteros is not available, other infielders they could and likely would deal include Pedro Ramirez (most Red Sox name ever, at least until someone named Conigliaro Yastrzemski gets to AAA), James Triantos and Jonathon Long…