How goalkeepers are treated at the youngest ages will have an impact on their long-term development, which is why it behooves a club to provide direction for coaches at the introductory levels.
I'm a huge proponent that at the very youngest ages everyone gets some exposure to goalkeeping at the expense of specialization and even immediate results. And, even once a youth player moves into the next stage, the early teens, goalkeepers should continue to get experience in the field as well.
Getting time in the field adds to the goalkeepers’ general knowledge of the game, which is so valuable to their soccer development in general, and as goalkeepers. It integrates them into the team training as opposed to segregating them, which has numerous benefits on a variety of levels. And, it keeps their touch sharp, which is so necessary.
The ratio between touches with feet vs. touches with hands when you're playing goalkeeper can be as high as, or higher than, 7 to 1 in a game.
By rotating goalkeepers at the youngest ages, coaches ensure that the kids who are potential goalkeepers for the higher levels are getting the foot-skill training they need to be successful goalkeepers, while learning to read the game.
Rotating keepers also gives the coaches a chance to evaluate which ones are suited to the position, while providing young soccer players a chance to self-select. In my experience, it is much more likely that young players will continue playing the game and reach their personal potential if they enjoy their role within the sport.
The selection process needs to evolve beyond the one or two players who don't seem to be doing well on the field -- or the ones who, at first glance, subjectively appear to be best suited for the position.
The coaches will also, as they observe various kids in the position, discover which players really enjoy the position and have many characteristics that make it a good fit. Attributes that are deemed weak for the position can be worked on over time.
Two qualities will stand out while rotating youth players into the goal: Eye-hand coordination and courage. When you add the third quality -- when you observe that they're enjoying it -- you can start giving them more opportunities in goal to develop their natural skills.
(A USSF "A" licensed coach, Paul Grafer has served as a FIFA Instructor, helping design and implement the International FIFA Goalkeeping Program. He served as U.S. U-17 boys national team in 2007-2012 and Chivas USA assistant coach in 2014. As a player, Grafer was an all-American at William & Mary and spent six years in MLS with the Rapids and the MetroStars. Grafer is professionally affiliated with SAFE-Skills, LLC and Athletes Helping Athletes.)