One would guess that a team like the Nationals, sitting on a .100 winning percentage, would be probably suffering from a run of bad luck and be due for some regression to the mean. In some areas they are, but in one really important area, they've had more than their share of good fortune.
The Nationals are second to only the Cleveland Indians with a .345 batting average on balls in play (BABIP). This stat, which essentially tells us the team's batting average when they don't strike out or hit a home run, is largely influenced by factors outside the batters' control, like fielding, park effects, and dumb luck.
For context, BABIP usually hovers around .300-.310 or so. The lowest team BABIP in this young season belongs to the Reds, way down at .251. Last year's highest team BABIP belonged to the Texas Rangers at .329 (who not coincidentally were the highest scoring team in the league), and the Reds again where the worst at .280.
Now, BABIP isn't totally about luck, as you probably could deduce from the Reds' consistently being the league caboose. Better hitters who hit more sharply hit balls can consistently maintain a higher BABIP. Also, groundballs tend to become hits more often than flyballs (though grounders never become homers, so all things considered flyballs are better than grounders for the offense, but I digress).
And indeed, the Nationals currently lead MLB with a 23.8% line-drive rate on batted balls. That's a really, really good number (although this stat is a highly subjective one that should be treated as a good estimate rather than a precise measurement). Those league-leading Rangers last year were second in MLB with a 22.1% LD rate in 2008 (the Mets were tops at 22.9%).
There are more sophisticated ways to measure expected BABIP, but just eyeballing it, if the Rangers' 22.1% LD rate got them to a .329 BABIP over the course of a full season, even if the Nationals could maintain a 23.8% LD rate (and they can't, but let's just say), they'd be due for some significant regression from their current sky-high .345 BABIP. And if you knock 15-20 points off that number, that's a significant number of seeing-eye grounders, bloopers, and also sharply hit balls becoming outs.
Those most overdue for payments to the BABIP piper: Guzman (.630!!), Hernandez (.455), Johnson (.481), and Flores (.438).
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Hat tip to budding SABR maven Chico Harlan for pointing this out to me. He emailed me about it a few days ago, but since he hadn't used it yet himself I figured I would. Still, if this little factoid pops up in an article, let it be known I stole it from him, not vicey-versey.