Ronaldo was sent off in Portugal’s penultimate World Cup qualifying match against the Republic of Ireland for an elbow. He initially received a three-match suspension for violent conduct.
FIFA later reduced the practical effect of that suspension by having him serve one match immediately (Portugal’s final qualifier) while suspending the remaining two matches under a one-year probationary period. That made him eligible to play from Portugal’s opening World Cup match onward.
That disciplinary decision has become known as the precedent for FIFA’s later decision involving Folarin Balogun, whose World Cup suspension was also controversially suspended under the same disciplinary provision.