Maybe it's playing in a ballpark with friendly dimensions. Perhaps it's a better night's sleep in a familiar bed and some good old home cooking. It could be the good vibes supplied by the crowd. Whatever the reason, there are certain players who simply perform better at home, just as there are some players who seem to shine only when they find themselves far from the scrutiny of the locals.
While major league managers have no problem setting up platoons, pairing up a left-handed hitter with a right-handed hitter to maximize offensive output, you're not going to find too many willing to sit a player for an entire 10-game homestand just because he is hitting .190 at home compared to .390 on the road. But as a fantasy baseball owner, you don't have to worry about a player rusting away on your bench, so long as he's continuing to get the playing time in real life. If you truly want to maximize your performance, taking advantage of an unconventional platoon based on home/road performance might be worth a look.