Due to the paucity of quality defensive CFs, Bradley Jr. is going to cost more money than I would want to spend. Moreover, he isn't far off from experiencing some kind of significant defensive decline. He is getting older and slower.
I would go young and cheap in CF -- that is, Marcus Wilson competes against Jarren Duran in spring training and the guy who has the better spring wins the starting job and ninth spot in the order. The LF will be H.Renfroe, the RF will be A.Verdugo with JD Martinez as the DH (Benintendi will be traded). By going cheap in CF (rather than resign Bradley Jr, who will cost at least 10 mil per year?) the Red Sox will have more resources to invest in pitching.
In the worst scenario, Wilson and Duran can't handle the starting job, and the Red Sox make a trade at the deadline for a starting CF, assuming they are alive and well in the AL East at the time.
I like the idea of taking chances and going with young unproven players. You don't want to do that with every position, but doing that for one position doesn't strike me as an outrageous risk. You can sometimes find good players in guys who aren't top 50 prospects. If M.Wilson can provide the Red Sox with a .220 BA with 20 HR, and above average defense, that wouldn't be so terrible. He isn't Joe Dimaggio but maybe he will be good enough for the ninth spot in the order.