The Pirates are going into the Break within a game of 1st place in the NL Central after having their worst season (57-105) since 1954. Astonishingly, they're over .500 on the road (24-21) after having one the worst road records in ML history in 2010 (17-64). Their offense has improved a bit, going from 29th in runs to 24th. The real reason for the improvement, though, is the pitching, going from 30th to 8th.
What's interesting is that they appear to be struggling in a number of key areas, including strikeouts, WHIP and batting average. They are maintaining an excellent team ERA despite allowing a lot of baserunners and not striking out many hitters.
Based on these numbers, it looks like a lot of their team success is riding on the pitchers continuing to not allow extra base hits. They've kept it up this long, so it does not look like a fluke, but it's not a lot to hang a playoff run on. In their last 18 games, they have improved their offense (12-6, 5 r/g), which shows that they might be on the right track (35-37, 3.66 r/g in their first 72 games).