Digged a little. Where i live the one-year sit rule is enforced at the high school level. Of course there are exceptions: family moving, school not offering specific program and more.
April 2019: The NCAA relaxed its transfer rules and awarded waivers to players with "documented mitigating circumstances that are outside the student-athlete's control and directly impact the health, safety and well-being of the student-athlete."
May 18: Currently, there exists a “year in residence” requirement that forces transfers to sit out one year before returning to NCAA competition – but that requirement is only in place for five NCAA sports: football, hockey, baseball, men’s basketball and women’s basketball.
...That means athletes with a GPA of 3.3 or better could transfer without sitting out a year, while those with GPAs of 3.2 or lower would have to sit out the year upon transferring. That would currently only affect the five sports with the sit-out requirement.
“What do people say about transfers? They say, 'Well kids today, they don’t want to go through any adversity. It gets the least bit difficult, and they just pick up and leave.' Well first of all, that’s not true, and second, if it were true, so what?”
In the past six months, Mars has become the go-to lawyer for parents of student-athletes wanting to transfer and play immediately. He set the bar high with his work with Patterson and his five Ole Miss teammates, all of whom were granted waivers.