General Mills has hired Olson of Minneapolis to handle a chunk of Yoplait Greek yogurt, which will relaunch next month with a new formula, packaging and messaging. Saatchi & Saatchi, New York, the incumbent shop for Yoplait, will remain on the brand for regular yogurt varieties. But General Mills picked Olson to oversee the launch of what is being described as a "full-calorie traditional" Greek yogurt that will debut in July, replacing the marketer's existing Greek version.