Most Coaches are ex players, though. You bring up Leach, who does he coach? Mastermind? Hal Mummee maybe, he taught Leach the game.
Leach is atypical among NCAA Division I head football coaches in that he did not play football at the college level. He was one of only six such coaches, with Paul Johnson at Georgia Tech, David Cutcliffe at Duke, Charlie Weis of Notre Dame, George O'Leary at UCF, Bobby Hauck at UNLV and Chip Kelly at Oregon.