What happened: The ACC board unanimously barred athletes who declared without withdrawing, signed professional contracts or appeared on league rosters. The policy applies to football and men's and women's basketball.

Why it matters: The move narrows roster options created by court challenges and the NCAA's new five-year eligibility model. Similar conference rules aim to protect places for current college athletes and incoming recruits.

What to watch: Enforcement disputes and potential legal challenges will determine how firmly the conference policies hold.