Rex wrote:
You reach 11-12 and you are still in the academy I'd say it is fair you have eliminated those with physical constraints.
Nah ... genetic and morphogenetic physical traits obviously continue to play a huge and difficult to foresee role in the development of a physique suitable for professional football in a variety of specialised roles after that stage of life.
Here are some examples: height, muscle fibre, joint flexibility, dominant side, rest heart rate and endurance, metabolism, bone density, build, centre of gravity, long-standing injuries or weaknesses.
All of these traits change considerably during adolescence and there's no absolute way to judge how they will combine to produce an adult individual physically optimised for top tier football.
For instance, players with extraordinary physical traits who are also easily crocked once they reach their full height and muscle mass are quite common - Diaby being one example.