Tevez's City career looked to be over after a fall-out with coach Roberto Mancini saw him go AWOL for three months of the club's Premier League title-winning campaign.
But the Argentine forward has returned to play an important role this season, scoring at Aston Villa on Monday, and his compatriot admits it has been a long road back.
"It's been difficult for Carlos, for Mancini, for the club. From something small, it grew so big," said Zabaleta, quoted in the Daily Star.
"After it happened, everything went crazy and it was so difficult.
"Everybody makes mistakes. The positive thing is Carlos came back again and the commitment for the club and team has been 100 per cent, so that is well done by him.
"Is he as good as before? Yes, definitely. He got a fantastic goal against Chelsea and he's been great all season."
While Tevez has impressed, things have not gone smoothly for the Premier League champions as they are out of Europe and set to surrender their domestic crown to rivals Manchester United.
But Zabaleta claims the team are still learning and clinging to hopes of FA Cup success in May.
"We should have done better than we did this season," added the 28-year-old full-back. "We still have the FA Cup, but we are still learning."