Yeah, that's the conventional wisdom, that a guy who hits a lot of doubles is squaring up on a lot of balls that may turn into power later. And at 21, Machado still has some growing to do.
Still, I'm not totally convinced that will be the case for him. A lot of his doubles he "steals" with speed. He turned a routine single into a double the other night just by legging it out and catching the defense by surprise.
I suppose he could bulk up over the course of his career (a bit like Cabrera) but unless that power were otherworldly, IMO it would be at the expense speed and defense, which are a part of his overall game. I think it would be to his detriment.
Though, perhaps, it would extend his career. :shrug: