SEATTLE, Nov. 27 -- The Seattle SuperSonics today named Nate McMillan as the team's new interim head coach, replacing Paul Westphal, and promoted Dwane Casey to associate head coach, Sonics President/General Manager Wally Walker announced.

McMillan, an assistant coach for the past two seasons after spending his entire 12-year career with the Sonics, becomes the 12th head coach in franchise history.

Known as "Mr. Sonic," McMillan retired after the 1997-98 season as the Sonics' all-time leader in assists and steals. He is now ranked second in both categories and is in the Sonics' all-time top-10 in eight other categories.

"Nate has always been a team leader, whether on the court or in the locker room," said Walker. "His historic selflessness as a player also adds to his great credibility now as a coach. We think the combination of Nate and Dwane will be the right match for our team."

On March 24, 1999, McMillan received one of the highest honors a basketball player can obtain as the Sonics retired his No. 10. He became just the fourth player in the 33-year history of the club to have his number retired, joining Fred Brown, Jack Sikma and Lenny Wilkens.

Casey, who has served as an assistant coach with the Sonics for the last seven seasons, came to Seattle after spending five years as a head coach in Japan.

Prior to coaching in Japan, Casey was an assistant under Eddie Sutton at the University of Kentucky from 1985-90, where he recruited and coached future NBA players Winston Bennett, Sam Bowie, Rex Chapman, LeRon Ellis, Shawn Kemp, Chris Mills, Dirk Minnifield, Irving Thomas and Melvin Turpin.