The Argentine has returned to City's starting line-up to kick-off the new season with two goals in two games and his condition has impressed de Jong who suggested that the former Manchester United man has been slightly unfit during his time at the Etihad Stadium.
"He looks quite slim. He always had a little belly but that is gone now at the moment! All credit to him," said the Dutchman.
"Don't get me wrong, it is always hard to get him off the ball, but I'd rather have a slim Tevez than one with a belly.
"As long as he scores goals for me it is okay. He is on fire at the moment and a Tevez on fire is good for any team wherever he is.
"I am just glad he is still part of this City team and if he continues like this he will score a lot of goals this season."