You can see how much more sink Bergesen was getting on the fastball last year. The second issue is the location of his pitches. Even with better movement, Bergy needs to stay down in the strike-zone to be effective. That's not happening quite enough:
The black lines give an idea of the top and bottom of the strike-zone, while the lines show the proportion of total pitches thrown at each height level. If Bergesen is throwing relatively straight 87 mph fastballs thigh-high, then he's going to get torched. According to FanGraphs, batters haven't missed a single pitch that they've swung at in the strike-zone (and only a quarter of those out of the zone). In 2009 their contact rate was an already high 91.2% (and 70.1% contact rate on pitches out of the zone). Hitters are always going to make good contact against him, so when they do Bergy needs to generate groundballs. This year, he's been a flyball pitcher with a groundball rate almost half of what it was last season (27.3% vs. 50.1%). Hopefully he gets things turned around soon.