Soxdetox just noticed something that surprised me a little. The Pirates have a better team on-base percentage than any team but the Rockies. That's particularly startling given that the Bucs' .333 OBP includes their pitchers, whereas AL teams have very few pitcher plate appearances weighing down their numbers.
So what's going on here? Andrew McCutchen having an even better offensive season than last year, with a .437 OBP, certainly helps. And Russell Martin, though he's missed significant time so far, has a remarkable .409 OBP.
After that, though, the main reason the Pirates' team OBP has been so high so far is that, besides Jordy Mercer (.256 OBP), they haven't had any OBP trainwrecks. Even Clint Barmes somehow has a .309 OBP. Even Chris Stewart has a .333 OBP. Even Travis Snider has mostly been terrible because he hasn't hit for any power; he has a respectable .322 OBP. The same goes for Jose Tabata, who has a .333 OBP.
The 2013 Pirates posted a .313 OBP. Some of the difference between this year and last has to do with players like McCutchen, Martin, Pedro Alvarez, Josh Harrison, Barmes and Snider getting on base more, with Mercer and Gaby Sanchez as the only key players who are reaching base less. Another key difference is that OBP sinks like Brandon Inge, Michael McKenry and Garrett Jones are now gone. Ike Davis (.350 OBP so far) hasn't replaced Jones' power, but he has been dramatically better at getting on base.
The 2013 Pirates batted .245 and walked 7.6 percent of the time. The 2014 Pirates are batting .260 and walking 8.5 percent of the time. Unsurprisingly, the Bucs' team BABIP is 16 points higher this year, ranking fifth in the majors at .310. I'm not sure if there's any consistent reason why that's happening -- the Pirates actually had a higher line drive percentage in 2013. So the Pirates' OBP will probably regress, at least to a degree. (Please feel free to share any ideas on this in the comments.)
Also, of course, "OBP" and "offense" aren't the same thing. The Pirates' offense is better this season, but only by so much -- they were 20th in baseball in runs scored last year (ninth in the NL), and are 16th this year (7th in the NL). Still, the Bucs' OBP proficiency has helped keep them afloat. The idea that the Pirates' offense has been a significant factor in the team's mediocre overall play this year isn't right. It's their pitching that's the problem.