That's only because you're assuming Hermida is the starting LF. I'm convinced one of Bay and Holliday is coming to Boston, leaving our lefty count at 3 -- Drew, LaRoche, and Ellsbury. Even if Hermida is our LF, that's only 4, as I'm not counting switch-hitters like VMart in among the lefties, for the simple reason that the only time having lefties out there is likely to be a platoon problem, is when facing a LHP, and in those situations VMart's batting right.
Besides, if you got Adrian Gonzalez, you'd be in the same pickle -- although perhaps for a better cause.
Sure, that's the big hole in my argument, but frankly we'd still be stronger than we were last year, especially if Youks puts up a league average season defensively. Since Beltre's not the kind who tends to age well though, I'd still stay away from him.