I'm a big fan of the new defensive metrics, but my family that lives in Boston says that Bay is a pretty decent fielder, and don't know why he has such a bad UZR. It might have to do with the Green Monster, but he had bad defensive ratings when he was in Pittsburgh too. I wonder if any Zoner's from Boston have an opinion on his defense.
I will say that this a pretty dumb move by the Mets. He's probably going to get worse, they don't need him, and he is taking up a huge part of their payroll. At least this should be a better signing than O Perez was.