Browsing through Denard Span's stats I found something that was... well not troubling but certainly of interest.
Home : .273 / .348 / .375
Away : .252 / .309 / .314
Home : .286 / .344 / .384
Away : .250 / .317 / .343
Home : .332 / .404 / .477
Away : .235 / .278 / .315
Last year was pretty crazy. At home he was Tony Gwynn. Away he was Tony Gwynn Jr. The other years aren't as dramatic, but as you can see he's been consistently much better at home.
Was this something to worry about? Would moving away from the friendly confines of Target Field (I just made that up!) kill Span's offense?
Or at least, I can't find any good reason to think that. There's nothing about Target Field that would explain that difference. There's no sign that it inflates offense. It doesn't favor lefty hitters (it actually seems to favor righties but then again Span is kind of a slap-hitting lefty). It doesn't have crazy dimensions or a strange surface that maybe he's taking advantage of.* I can't find anything about Minnesota that explains this. Sometimes you dig and find nothing and it's kind of important to accept that.
* Though I'll note here the Metrodome DID have that fast artificial turf. Combine that and young legs and that's really why Span was a .300 hitter early on. So if you think a return to a .290+ hitter is in the cards...I wouldn't bet on it.
What's the reasoning? Simple. It happens. In general players hit better at home than on the road. They are comfortable there. They're not living out of a hotel. They both see the backdrop more regularly and have more than a couple games to get used to it since they are in one place during a homestand. For some guys this helps a little, for others it helps a lot and Span is one of those guys it seems to help alot. He hit better at the Metrodome as well.
Like look at a Cody Ross. In 2010 he hit alot better at Marlins Park than away. In 2011 he hit a little bit better overall at AT&T than away (and that's a tough place to hit). In 2012, he hit tons better in Fenway than away (an easy place for a righty to hit). He's just one of these guys.
So what? So expect this next year. I wouldn't expect the dramatic shift we saw last year from Span. For some reason Target Field was great for hitting last year. Nationals Park is routinely very average. But I wouldn't be surprised by a difference in stats (though not same stats) a lot like 2010. Noticeably better across the board at home than away. It's not going to make him any more or less useful for the season than the Nats expect him to be, it'll just bunch up his usefulness a bit.