It doesn't make much sense. I'm not sure what the method to Willie's madness really is here, but it's frustrating to see, especially from a fantasy perspective. And as a fan, I want so badly to see Reyes, Wright, Beltran, Floyd, Piazza. In that order... But I have seen him quoted as saying he likes having a big bat down there towards the end of the lineup. Which you can't argue with too much, because I don't know how many years I has to watch Ordonez, Timo Perez, Jay Payton, et al. down there for automatic 1-2-3 innings.
I'm not sure how much longer he'll be thrilled with them hovering around .500, though, so some changes might be coming soon... I expect him to be up there by mid June.