As I've said probably too often by now, I based my worry on personal observation at the back fields at spring training a couple years ago. He was scattering or short-hopping routine throws as often as making accurate ones. I was not optimistic he could improve by now - my concern was that his arm strength might have maxed out that that point. I am glad to see he has indeed improved - he's making major league plays, not merely routine ones. (BTW I am sure I, as just some guy on the Internet, am not the "original source" for anything whatsoever.) And conversely, the mistakes Sano makes look correctable with experience, while his ability to come in on a slow roller and fire to first always told me he has all the tools needed to succeed. Improvement comes down to his commitment to work at it, which so far this year looks promising. He may not achieve complete reliability in time before his weight becomes the deciding factor some year, so that's the other worry for me.