As September approaches, teams are mostly split into three categories: those preparing for the playoffs, those trying to make a run at contention and those whose focus has turned to next season.
There's still a fair amount to play for within those groups. The clubs that are pretty safely in playoff positions are still battling for postseason positioning, whether in the wild-card race (the Yankees and Red Sox) or in division races (the Dodgers and Padres).
The second group -- those trying to play their way into a postseason berth -- has shrunk considerably, as more and more squads have fallen out of their wild-card races.