There are circumstances where a kid may be recruited before making varsity. But in most cases it’s a reasonable suggestion for a typical high school baseball player.
I played on a Legion team with guys from a powerhouse high school. Their three primary pitchers were drafted out of high school and went D1. Sitting behind them were two juniors and a soph who never saw a varsity mound until those three left.
The three following pitchers got D1 offers before seeing the varsity mound. They were seen pitching in Legion non conference games and MLB tryout camps (no travel ball then).