I actually really like this for Boston. Even if it does last the full five years.
I imagine he won't be a full-time DH and they'll rotate. But it should help Martinez, who is a bit fragile and is not exactly a defensive wizard. But he'll be fine when required to play in the field. After all, this is the same franchise that had Manny Ramirez in LF.
With the Blue Jays window shut, it's back to Boston and New York duking it out for a division title and wild card play-in bid.