It is absurd to say that one has to be a footballer to become a professional manager. Just because you were good at the sport does not mean you can manage or coach a team. Although it can have its benefits, by far, it is not a necessity and in fact, best rarely makes the best coaches.
If you are a player, then you do have an opportunity to learn about managing from your coaches and managers, but this does not reflect every aspect. There are other issues than what meets the eye. The manager spends numerous hours on planning, preparation, and orchestrating other kinds of stuff. As they say "Manager needs to trouble the comforted and give comfort to the troubled."
One of the most overrated thoughts out there is that if you weren't a great player, you can't be a great coach. It's a big fallacy.-- Frank Martin
#3 Guy Roux
In the middle of France, about 165 kilometres southeast of Paris, lies the little city of Auxerre.
Way back in 1961, a 23-year-old was handed to lead a pretty unknown and unheard club in Europe. His name was Guy Roux. He had no experience and background and was just an amateur football player. He had joined Auxerre as a player in 1954.
Auxerre was a small local club which never progressed into the national leagues. Roux understood his capabilities as a player, and he made his decision to apply for the post of manager in 1961.
He agreed to work for low wages and maybe that was one of the reasons he got this opportunity. In his 44 years stay at Auxerre, he transformed a small, unknown amateur club into an internationally known club.
In 1995/1996 he led the club to the Ligue 1 title. He has certainly immortalized himself as a living legend and one of the greatest managers who never played professional football.