The five-time Ballon d'Or winner was an integral part of Real's four Champions League titles in the past five seasons, while the honour has eluded the Italian giants since 1996.
Last season, Ronaldo scored an iconic overhead kick in the last-16 which knocked his potential new side out of the competition - which saw the home supporters at the Juventus Stadium applaud the 33-year-old.
And former AS Roma and Los Blancos forward Julio Baptista has tipped the Portugal superstar to have a massive impact once his €100m move is completed.
"Serie A needs to change a few things to get back to the level of the past," Baptista told reporters, as quoted by FotMob. "Cristiano is a great player so it [Serie A] will improve, definitely.
"I think a few changes are needed to improve Serie A. It is not as good as it was 15 or 20 years ago.
"Juventus would have a stronger team with Cristiano, more competitive, they would have an advantage [in the UEFA Champions League].
Ronaldo is Madrid's all-time leading goalscorer, having netted 450 goals in nine seasons at Santiago Bernabeu, and Baptista said the club would struggle to replace the 33-year-old forward.
"For Madrid, it would be a very big loss. As much as people can say what they want about Cristiano, he has been a player who has left a tremendous mark on Madrid and the Spanish league as well.
"He has the best records in the league and in Madrid."