Kevin Armstrong will step down the the end of the week.
"We're just sick about it," said Mike Baker, vice president of national marketing for the Lexington, Ky.-based chain, which was recently acquired by Yum Brands.
Mr. Armstrong's duties
The chain recently awarded advertising duties to Yum roster shop BBDO Worldwide, New York, part of Omnicom Group, following a review.
Mr. Armstrong could not immediately be reached for comment.