Taken directly from the Braves site:

With Aybar's arrival, the Braves may have found themselves a legitimate leadoff hitter who could fill that role for many years to come. They immediately put the 23-year-old switch hitter at the top of Sunday's lineup and moved both Marcus Giles and Edgar Renteria down one spot in the lineup. The move allows Giles to return to the second spot of the order, where he'd found more comfort in the past.

Kinda makes me wonder if a Chipper Jones trade is planned in the offseason, or perhaps a scenario involving him moving to first base and Adam Laroche moving on to another team is more likely?