He's their best OBA guy so it makes sense for him to be leadoff. Vidro should be 2nd, Johnson 3rd, and Guillen 4th. That's the way it should be anyway... Guzman has no business in the top half of the lineup, he's an awful hitter.
"Jack, will you call me, if you're able?"
"I've got your phone number written, in the back of my Bible."
Why would they move him down? The leadoff hitter should get on base, and lo and behold, that's exactly his forte. Anyone can knock in runs, not everyone can get on base. Besides, he'll probably see more steals in the leadoff position.