The Portugal captain was troubled by patellar tendinosis in Brazil as his country were unable to progress from a group that included eventual winners Germany, Ghana and United States.
Mendes told reporters that only the former Manchester United man would have played on through the injuries.
"It's clear Ronaldo would have rested more if he weren't so professional... he always wants to play," explained Mendes, who is also responsible for the likes of Radamel Falcao and James Rodriguez.
"If it had been someone else, they wouldn't have played."
Mendes also stated that Ronaldo's injuries were now "in the past" - with the 29-year-old Ballon d'Or holder scoring 36 goals in all competitions already this season.
"Off the pitch he is a role model for kids because of how he leads his day-to-day life," Mendes added.
