In his three years in the majors the young Jay Bruce shows signs of growing into a good power hitter for the Reds. In that time, opposing pitchers chose to attack him low and away:
Note that he does well on balls concentrate in the area pitchers like to work him, he's just not as productive as when the ball is on the high, outside corner. Note the hole, however, high and inside. That's something that more pitchers might try to exploit, since it leads to favorable results.
That high, inside area is where Jay delivers pop ups, and pop ups are one of the most desirable batted balls. A pop up is almost a sure out. A pop up will hold a runner at third with less than two out. A pop up can invoke the infield fly rule, guaranteeing an out.
Bruce showed much progress in 2010. While he always showed power, he was a bit of an out machine his first two seasons, with a .309 OBP. That went up to .353 in 2010. With Jay becoming a tougher out, pitchers will need to do more than pitch him away. It looks like up and in is the place to start.