Ferdinand believes that Manchester City should have won the Premier League title last season if Rodri had remained healthy throughout the season.
Arsenal were crowned Premier League champions for the first time since 2004 last May, leading Manchester City by 7 points, but Rodri missed 17 league games due to injury.
Goal.com reported Rio Ferdinand's comments on the YouTube podcast "Rio Ferdinand Interview": "If Rodri had started and played the full 90 minutes in every game last season and hadn't been injured, Manchester City would have won the title. I'm not trying to downplay Arsenal's contribution, but if Rodri had played 10 more games, Manchester City would have won the title."
He continued, "This is no coincidence. He went to the tournament with the Spanish team, was the most important player on the team, won the World Cup Best Player award, and helped the team win the championship. He also won the Ballon d'Or; he won everything."
The former Manchester United star believes that Manchester City is facing huge challenges, especially after Guardiola's long and successful managerial career ended and Rodri is about to leave the Etihad Stadium.
Ferdinand warned: "Manchester City not only lost Guardiola, but it looks like they're going to lose Rodri (to Barcelona) now. These two have been the most important people at the club for the past seven or eight years."
He continued, "After changing managers, they have now lost their most important and influential player. I think Manchester City will face a huge challenge this season if they want to maintain the competitiveness they have had for the past eight or nine years."
However, Ferdinand also praised Rodri's abilities and said that if he joined Barcelona, the team would become more threatening.
He said: "If Barcelona signs him, he will be a real problem this season because Rodri is now the most important player for any team in the world, and he has been for the past few years. He is a top player and a very good professional player."
