Doing things secretly causes problems. Why not just open the tryouts up to all 8th graders. In one school a number of girls were brought up from middle school quietly to tryout for varsity (and not because of a numbers need). Others with equal talent (not an opinion, fact) weren't given this opportunity. To avoid problems why not invite all? Most that are not close to being ready will pass on the tryout and the coaches can take those who they had planned on taking anyway. Plus, in an ideal world, maybe a sleeper without the right connections will catch the eye of a coach.
