From what I have heard, he isn't ready for MLB. He would probably spend a good chunk of the season in AAA. I feel that he might be a fallback at SS if Hiro doesn't work. In addition, if for some reason we don't have a capable 2nd baseman, I imagine Hiro could move there, and Diaz could play ss. In addition we really don't have much depth at ss between Hiro and Russell. Lastly. if Hiro is great, and so is Diaz, we could trade one for prospects. But, with all of this being said, I don't imagine the A's will be willing to spend big on him, so I don't see him being signed by the A's. But you never know.