I will answer this.

My son is an on-age 2020 (May 2002). For the most part in Maryland (and elsewhere?), teams have their last tryouts for the boys in their freshman year and that team continues playing in summer (and some fall) tourneys throughout the high school years. Yes there are some additions and subtractions, but for the most part the "core" stays the same. So to the 2020s, in particular, how clubs implement the changes could be critical to this age group.

I have asked our club owner what he plans to do, and he has not yet decided whether to "bite the bullet" next year yet. He said he looked at the rosters and thinks that the private school holdbacks on the 2021 can replace the private school holdbacks on the 2020 and upwards. Since lacrosse is still a relatively small community, I am sure the bar room meetings will be taking place during the summer season.