I'd be willing to bet heavy money that when he signed with the Cubs they tried to make swing changes to unlock that untapped power and apparently screwed him up permanently in doing so. It was in fact reported at the time that the Cubs believed they could make changes to unlock his power. If you recall, they tried to do the same thing with Starlin Castro and it completely tanked his performance for 2+ seasons I wonder why the Cubs have had such a difficult time developing prospects What we wanted: What we got: