David Ortiz (BOS) hit six home runs so far this season, but only pulled half of them to right of centerfield. While Ortiz always showed good power the other way, especially pounding the wall at Fenway, he appears to be going to left quite a bit this season. The reason comes down to a shift in his power.
Note the very hot slugging area down and in. If you divide the strike zone into thirds, top to bottom, Ortiz hits home runs to all fields in the top to thirds, but strictly pulled the ball in the lower third in this time frame. Down and in is the traditional place for lefties to hit long drives, as they can get a nice upper cut swing on the pitch.
In 2011, that low power isn't there yet.
His power lies mostly in the top half of the zone, the area where he is most likely to drive the ball the other way. Pitchers know to avoid that area, but the mistakes there are hit for doubles or outs. We'll see if that keeps up, and if pitchers start to take advantage of a spot that might have turned into a weakness.