In my opinion, this is a much better signing than Werth's. Same length, younger, better hitter, much better fielder, more consistent despite being younger, and better injury history. For the Sox, tha
Considering the quite unimpressive FA pool next year, this lets the Sox sleep better about Ellsbury, Cameron, and Drew's uncertain futures and let's them be less dependent on Kalish's development timeline
For the Sox, that's worth the ~2 million a year it cost to sign the bet FA position player over the 2nd best, which is much more likely to fail.