The Dodgers are in contention, in part because the Giants haven't been able to pull away. Los Angeles was 30-13 on May 22 and 42-25 on June 17th, have slipped all the way to 57-50. They lost Matt Kemp and Andre Ethier to injuries for some time, and while they have returned, the power has not. They don't have any other legitimate power threats in the lineup, although they're hoping that Hanley Ramirez can return to form (he hit 33 HR in 2008).
As you can see (and as common sense would dictate), having the lowest slugging percentage is a serious problem. The Dodgers aren't in danger of losing 90 games, but none of these teams made the playoffs (the 2003 Dodgers had the best ERA and scored the fewest runs, and missed the playoffs).
If Matt Kemp and Andre Ethier start hitting some home runs (or someone else like AJ Ellis, who hit 2 tonight), then they should be in decent shape. If they continue to have the lowest slugging percentage, they'll have to defy history to make the playoffs.