At our HS, there are summer camps for elementary through middle schoolers, open fields in the summer and fall for whoever wants to come, including 8th-graders, and winter workouts from Jan-Mar. All optional, all organized by the HC, so it meant that he had a pretty good idea of what he had when the "tryouts" happened. Only 9th-graders and up played on HS teams, I guess performance at tryouts might have impacted which team you played on. I can't imagine someone just showing up cold at tryouts, except maybe 3-sport athletes and then they would be known quantities anyway.