It makes sense to me. He has enough size to play center and has range on his shot to pull defenders out of the paint. I assume he signed for the minimum or so. It sounds like a fine signing.
Ronny, I'm assuming you mean "worst defensive starting center," or something along those lines, and even that's a reach. Miller's horrid, but Eddy Curry was far worse. Much, much worse. And I'm sure the lot of us could come up with a few other non-starters, my brain's too fried to right nowish.