The shift is the result of clashing expectations between Mr. Brennan and Tom Long, who joined Miller as chief marketing officer in July. Mr. Brennan, who lives in a Chicago suburb and spends a few days a week at Miller's Milwaukee headquarters, wanted more flexibility in his work schedule, executives familiar with the situation said, while Mr. Long wanted someone more hands-on in the media role.
"Bob came into the organization for the intellectual challenge of creating a new media environment for Miller, but from a personal standpoint he needs to step out of the day-to-day management of our business," Mr. Long said in the Aug. 16 internal memo.
"There will be no change in the direction that we have set for media. In fact, Bob will continue to work with [Media Director] Dave Genel and me on the evolution of the contact strategy," the memo also said.
Mr. Brennan, 46, referred questions to Miller.
Miller hired Mr. Brennan as director-media services earlier this year after Steve Buerger left to join Time Warner's corporate sales and marketing operation.
Mr. Brennan joined Burnett in 1982 as a media planner and quickly moved up the ranks. When the media department split off in 1997-creating Starcom-he was named president.
He became president of Leo Burnett Worldwide in 2000 and left in 2003. His noncompete clause expired last fall, but he was known to enjoy his personal time with his family. He also became a fitness fanatic and joked that he was offered a $50-a-day job by his personal trainer to demonstrate proper workout techniques.
Many in the media-agency business expected Mr. Brennan to return to that world, and he held talks with various players in the space, including Interpublic Group of Cos., before deciding to try his hand on the client side.
At a Miller wholesaler meeting this spring, SABMiller CEO Graham MacKay said Mr. Brennan and Mr. Long, a former Coca-Cola Co. executive, were examples of how Miller was trying to boost its marketing efforts.
contributing: lisa sanders