Which player was nicknamed "The Chairman of the Board"?

What uniform number did Mariano Rivera wear with the Yankees? What position did Whitey Ford primarily play? Whitey Ford is best known for playing with which MLB team? What uniform number did Whitey Ford wear with the Yankees? What position did Don Mattingly primarily play? Don Mattingly is best known for playing with which MLB team? What uniform number did Don Mattingly wear with the Yankees? What position did Phil Rizzuto primarily play?