Yes, many of the greatest managers were mostly average players (Ferguson, Clough, Happel, Michels, Mourinho, Klopp, Guardiola, Ancelotti, Capello, Hitzfeld, Trapattoni, Lobanovskiy, Hererra, Busby, Lattek, Guttmann, Rocco, Shankly, Stein, and Paisley)