One word for you: "cut". Turn out for the basketball team short, slow, and unable to shoot, and you will not be suiting up. Hell, turn up as a "project" and you may be cut. A kid at my high school did not make the team until his junior year (as I recall). He got an athletic scholarship to college, was in the running for NBA rookie of the year, and eventually picked up a championship ring, not as a star but as a respected bit player. When he was 14 he could be cut from the team. I doubt his Algebra I teacher had any such option.
Another word: "recruit". Even the public high schools end up with a lot of athletes who do not live within the nominal boundaries. The high school a co-worker's son once attended is now a power in football. Why? The parents of a star athlete concluded they liked the program and found an apartment in town. A city high school is a power in girls' basketball, with players from all over the city. And then there are the Catholic high schools, the private schools, etc.
Another word: "recruit". Even the public high schools end up with a lot of athletes who do not live within the nominal boundaries. The high school a co-worker's son once attended is now a power in football. Why? The parents of a star athlete concluded they liked the program and found an apartment in town. A city high school is a power in girls' basketball, with players from all over the city. And then there are the Catholic high schools, the private schools, etc.