September is time for modified goals. No longer are you seeing what players can do in the long term. Now you are just trying out guys to see who you might invite to Spring Training next year. And no longer are you shooting for a playoff spot. Instead you are aiming lower : .500 record, more wins than last year or in the Nats case - finishing third would be nice.
To finish third the Nats need to catch the Mets. The Mets have a 2 game lead which normally is nothing. But this late in the year that's nothing to scoff at. The Mets have 15 games left. If they go a completely reasonable 7-8 to finish up the Nats would have to go 10-6 to finish ahead of them (by percentage points 78-83 to 78-84 - the Nats won't make up that game v the Dodgers) 10-6 is a good finish. The Nats aren't a good team.
The Nats do have two things going for them. First they have a head to head series with the Mets right now. Each win = Mets Loss = gained ground. They won the first game last night. Take two of the next three and suddenly they are only a game behind. Of course it works both ways. Lose two of the next three and it's a 3 game Mets cushion with 12 or so games and the Nats are looking at having to go 10-2 or hope for the annual Mets collapse.
The second thing is schedule. Both teams take on PHI and ATL one more time. For the other two series the Nats have the Marlins. The Mets have the Cardinals and the Reds. The Nats should win more of these games than the Mets (though they never seem to do that do they?)
The Nats had some lofty goals as late as mid August, but those have passed. Now it's time to go after something more reasonable but symbolically important. Pass the Mets. Everyone thinks the Nats are a rising team. If they pass the Mets and finish 3rd then the talk next year will be about making the next step to take on the big boys. That's the talk the Nats want to hear.