This is the time of year when the Pittsburgh Pirates typically fall apart. That's because the team has a number of fundamental weaknesses that aren't so apparent earlier in the year, but are exposed by the late-season grind.
With the notable exception of Andrew McCutchen, the Pirates aren't particularly good batters. They have to rely on the rotation, and especially the bullpen, for their victories. As such, they are often prey for teams that have decent, though not superlative, pitching, and better hitting than they do.
One of these teams is the Milwaukee Brewers. The Pirates have done particularly poorly against this one team for the better part of a decade, even though the "Brew Crew" is seldom in contention, and at times are even below the Bucs in the standings (as is the case now).
Earlier in the season, the Pirates barely managed to be 3-3 against them, a decent but not great result against a sub-.500 team. Since then, they have gone 1-5 against Milwaukee. A similar story could be told of their 1-5 record in a short season series against the similarly fourth-place San Diego Padres.
The Pirates' success in 2012 (and 2011) has been a result of their curing one fundamental weakness: interleague play. After sporting losing records in such games in the past decade, they went 10-8 against American League teams this year, and even compiled a winning 8-7 record last year. As a result, the former drag inflicted by the month of June has become a positive for them.
In fact, the story of the Pirates can be told as the story of three seasons. As late as May 23, they were a respectable, but losing, 20-24. Then they went on a tear until the All-Star break, going 28-13 and winning more than two games for every loss over that stretch. Since then, they have been 22-27, reverting to their April and May ways.
For most of the season, the Bucs have been at the BOTTOM of the league in batting. Under those circumstances, even superior pitching couldn't give them a winning record. During their winning midseason stretch, they had average batting, which is to say that their rotation could carry the day.
But with the batting having gone flat, and the pitchers getting tired, they will have trouble eking out the one-run victories they managed earlier in the season.
Jeff Karstens recorded two out of his four losses in August. James McDonald has been 3-4 since the All Star break. Of the six games in which Kevin Correia pitched in August, there were only two wins, versus four losses. Joel Hanrahan recently posted his first loss (versus four wins) in relief.
The Pirates appear to have overcome their earlier midseason struggles. That's why they were contenders through July in 2011, and through August in 2012. But they won't make it to the postseason if they can't get to the finish line.