I just dug up Hafner's splits from the last two seasons.
In 2003, Hafner hit .190 against lefties last season with an OPS of 629 (opposed to .280 with an OPS of 886 against righties).
This season, Hafner is hitting .261 against lefties with an OPS of 629 (opposed to .361 with an OPS of 1146
So, he is still much better against righties, but he is now decent against lefties.
Here are the OPSs (against lefties) of the players who typically hit ahead of Hafner in the order when a lefty throws:
Ron Belliard, 917
Omar Vizquel, 666
Matt Lawton, 747
Victor Martinez, 858
Casey Blake, 822
Thus, batting Hafner 6th against lefties is justified. Hopefully he can progess enough next season to remain fixated at the top of the lineup in 2005.