George Karl takes the credit. Mike Kahn wrote an interesting article about Karl for FoxSports.com, which describes Karl and the many coaches--Nate McMillan, Dwane Casey, Bob Weiss, Terry Stotts--who have worked under him.
McMillan was struggling through the 1997-98 season as a player in Seattle, and Karl ironically finishing his last season as coach there with a staff that included Stotts, Casey, Weiss and Tim Grgurich encouraged McMillan to sit in on coaching meetings and get involved in game preparation.
"I just knew Nate had it," Karl said. "Nate is a leader just in his personality, and is such a competitor, he just had head coach written all over him. He was so focused on doing whatever he could as player, it just never occurred to him until then."