Yeah it looks like it's just for players who play on the fall/spring league teams, which is mostly mioddle schoolers/freshmen.
I know at the clubs here locally, it's the same setup. Select teams that have a fall/spring league play year round. U16 & up don't have a league and only one of the clubs here has spring training for those players (and that's a complex setup that I don't feel like expounding on).
For the most part, the clubs down here don't do much during HS season
