If you think .280 would be the outcome of non stop fastballs to him, then your opinion of Polanco's hit tool isn't very high after all. Nick Punto or (heaven help us) Drew Butera might even achieve that. I do agree with your scenario if .280 is all he can muster. If instead it's more like a professional hitter and is .350 (fastballs only, remember), then the pitchers will adjust, the batter will adjust, and we'll be back to a more interesting mix of walks. Add in some scouts' projection of decent power, and the pitchers have to adjust some more, and, well, there ya go. I don't want Polanco force-fed at the MLB level in 2016. But if he forces his way up from AAA, mid-season, or waits until 2017, I think he can be pretty good. The jury is still (a little bit) out on whether he can improve his throwing to keep a SS job, with probably a majority opinion by now that he can't, but he might arrive just in time to replace a fading or (one would hope) traded Dozier at second.