Cal athletic director Jim Knowlton announced his retirement on Monday after seven years at Berkeley.Knowlton will stay on through July 1. Deputy athletic directors Jay Larson and Jenny Simon-O’Neill have been appointed co-directors for Golden Bears athletics.Under Knowlton’s leadership, Cal captured 10 national championships and appeared in four bowl games in football.”It has been an incredible honor to serve at the University of California, Berkeley, the No. 1 public university in the country,” Knowlton said. “The expectation of holistic excellence helps to drive everyone associated with the university, and our department is no exception. The combination of a world-class education, athletic excellence, an inclusive community, an awe-inspiring location and, most importantly, truly special people, make Cal a magnificent place to serve.”UC Berkeley chancellor Rich Lyons announced he will use the transition period to install a new leadership structure.