i'm almost sure the rules is once they are done practicing with the high school team they are free to compete kids regardless of whether the varsity season is still going on. have to be careful with this though because i saw a situation in baseball where a kid played jv and started with his summer team after the jv season was over. due to an injury the varsity team had a spot for him on their roster at state but he couldn't go because he had already begun practice with his summer team.