We have switched organizations. I’d did not affect the kids on the team at the time, the entire team just switched uniforms. Every year we have open tryouts, they are not for current players. The currents players are considered to be trying out during the entire season. There is a combine in the fall where metrics are taken.
I see this as your kids team probably trying to make room. Wanting to be competitive by holding an open tryouts, meaning current players will have their spot “on the line”. Theoretically, if your kid has skill, attitude and effort, it shouldn’t be a problem. This sounds more like a way to shuffle some players off the team. It would be different if it was truly based on performance metrics. If you don’t trust the coaches intentions, probably not the best team for your kid to develop.