That's something that was discussed a bit last year. I believe the story of the encounter with his then-new batting coach was Hardy began his batting practice by spraying a bunch of balls to right field and center. He was done, marched out of the cage and the hitting coach, Jim Presley, said "What are you doing?" to which Hardy responded "Hitting a few the other way, going up the middle, you know." Presley then told him that he had watched him mash home runs with the Brewers (while Presley was with the Marlins) and to knock off that opposite field crap. He did and showed much more power. Camden Yards did not hurt either.
Brandon Warne's interview with Joe Vavra at Twinkie Town is essential reading for those looking to get into the organization's mindset. In regards to this specific topic, Vavra said this:
So there’s a bit of a preconceived notion that the organization is more of a "go the other way/don’t care much about home runs" philosophy-wise. Care to put that to bed ?
JV: No, it’s not that at all. I mean, we have a lot of young hitters, and we teach young hitters balance. You certainly don’t want to take their power away. Or say, take a pull hitter and make him go the other way. You don’t want to take away the strength from the kid; that just shocks him. You want him to be able to use it, but you also want to be able to push the outfield back on the opposite side of the field. Probably 70 percent or more of the pitches are likely to be away, so they do have to learn how to hit the ball the other way, and have some kind of balance to the playing field. If the field is tilted, they better have outstanding power to the pull side. You see a David Ortiz, who we had in this organization, and well, the ballpark changes the way you go about your hitting. I think the perception with Target Field is that you can’t hit home runs here, and they get that in their mind. I’m totally of the opposite mindset; you can drive the ball out of this ballpark. It’s certainly playing smaller than it did last year. This singles, slap-hitting stuff, that’s Denard Span to a degree, and it’s Ben Revere. They’re that type of guys; they’ve gotta get on base and gotta attack the opposite side, but they also gotta be able to pull it. You can’t be just on one side of the plate, so to speak, and that includes those two guys.