Ronaldo was replaced for the first time this season in the recent win over AC Milan, coming off for Paulo Dybala who went on to score the only goal of the game.
The forward appeared to react angrily to being substituted, walking straight down the tunnel before reportedly leaving the stadium before full-time.
Ronaldo then told reporters he was “very well” and “very fit” before Portugal’s Euro 2020 qualifiers, but has now backed up Sarri’s injury claims and agrees with his manager’s decision.
“In the last three weeks I have been limited,” he told A Bola.
“Everyone knows that I don’t like to be substituted, but there was no problem in my gestures after the change. I tried to help Juventus by playing injured.
“No one likes to be replaced, but I understand it, because I wasn’t well in those two games. I wasn’t 100%.”