Nike officially launched the new Corinthians 3rd away kit for the 08/09 season. The shirt has the new sponsor Medial Saúde on it. The colour purple is a tribute to the fanatic supporters of Corinthians who are so crazy about the club that they turn "purple" for it. Basically it's a tribute by using the colour purple for the shirt.
Here is a unique video with scenes of the official photo shoot