Overseer of N.C.A.A. Men's Basketball Tournament Won't Return The N.C.A.A. announced Tuesday that one of its most important executives, Greg Shaheen, would not return as the executive vice president for championships and alliances. Mark Lewis, the president of Jet Set Sports, a hospitality and event company, will replace him. For about a decade, Shaheen, 44, ran the N.C.A.A."s signature event and biggest money maker, the men's basketball tournament. There is a chance he may return in a less prominent role. The possibility that Shaheen, who held his current job on an interim basis, would not return became a topic of discussion at the Final Four, and several coaches were critical of that prospect. Kansas Coach Bill Self and Michigan State Coach Tom Izzo were sharp defenders of Shaheen then. On Tuesday, Duke Coach Mike Krzyzewski told CBSSports.com, "It's a huge loss for our game." Lewis has worked as a vice president for sponsorship at NBC and for Olympic-related organizations in the past. He will be in charge of the N.C.A.A."s 89 championships.