I'm in that camp too, although his challenge is approximately the opposite of Vielma's: if he can't get a little more juice on his throws to first, without losing accuracy, he will be playing 2B in someone else's system in 2017 at latest. Vielma has a huge chance to fail to progress at bat - he needs a little pop in the bat, just a little, as others have stated, and I really wish he would walk more, so that during any times he's hitting .300 it's not the proverbial empty .300. Without a little pop, it may be difficult for him to work enough walks, as there's not much disincentive to throw him a fastball on 3-1 and take your chances on him reaching first the old-fashioned way. Nevertheless, I consider him enough of a prospect to keep serious watch on.