This question comes up lot when I speak to youth soccer players’ parents. It is tricky to answer because every situation is different. There are some players who seem to be made for a specific position and others that can be put virtually anywhere on the field and look comfortable.
My answer is that once a player is U-12 to U-13, the coach should have an idea about where on the field he or she is most likely to find success. It is a little easier with defenders than it is with offensive players because most of the time an outside midfielder will be able to also play forward and visa versa.
Starting from U-8, coaches should be playing players at every position so that they start to learn the different responsibilities that accompany each spot. This also gives the coach an idea about each player’s attributes and how best to utilize their skills. For example, if a player loves to make runs forward but has a hard time getting back, that player is not likely to do well as a central defender. A coach would be better off playing that player in an offensive position and coaching him or her to work just as hard getting back to defend as he or she does to get forward.
Even at the professional level each athlete needs to understand the different roles of each position. Building that knowledge starts when players are young. If a player understands the role of the player that he or she is playing against, he or she will be better able to attack or defend them.