The Portuguese superstar was sent off in the first half of Juve’s 2-0 win away to Valencia last week after a clash with Jeison Murillo.
He risked a potentially lengthy suspension, but instead the 33-year-old will only sit out his team’s game at home to Swiss champions Young Boys next week.
Juve then plays Jose Mourinho’s United at Old Trafford on Tuesday, October 23, before hosting the English club in Turin on November 7 in Group H.
Ronaldo, a five-time Champions League winner, first won the competition with United in 2008 before leaving for Real Madrid a year later.
He moved to Juventus in July after nine years in the Spanish capital and has so far scored three goals in Serie A for his new club.