Former Juventus goalkeeper Gianluigi Buffon said the Serie A rival club "lost its collective identity" after signing Ronaldo in 2018.
Ronaldo, who returned to Manchester United this season, scored 101 goals in 135 matches with Juventus and won the league title twice, but the team failed to cross the Champions League quarter-finals in 3 seasons with the Portuguese striker.
Buffon left Juventus last summer to return to Parma, with whom he began his career nearly two decades ago.
Buffon played the 2018-2019 season with Paris Saint-Germain and won the Italian League title 10 times.
Buffon told the American network TUDN that "Juventus had the opportunity to win the Champions League in Ronaldo's first season when I was with Paris Saint-Germain, but I did not understand what happened. When I came back to play with Ronaldo for two years, things were going well." But I think Juventus has lost its identity."
"We reached the Champions League final in 2017 because we had a lot of experience, but above all we were one unit and there was competition for all positions in a strong squad. We lost that with Ronaldo."
Juventus is fifth in the league this season, 12 points behind Inter Milan, the defending champion.
Juventus host Napoli on January 6, when the championship resumes after the winter break.