The Argentine striker completed a move to Juve on Wednesday evening after the clubs had earlier agreed a fee of around £10million.
Tevez's transfer brings to an end a four-year spell at the Etihad Stadium and, although he has had a few well-documented problems, Barry insists he will be missed.
The 29-year-old has been instrumental in the club's success over the past few seasons, when they have been crowned Premier League and FA Cup champions, and Barry has no doubts that he will continue to shine in Italy.
"It will be a massive loss for Manchester City," the midfielder told Sky Sports News.
"He has had a fantastic few years there and he has been fantastic to play alongside.
"To hear that news is quite sad but he will go and do a great job wherever he goes."
Tevez signed a three-year deal with Juventus on Wednesday after agreeing personal terms and passing a medical.
He has been handed the famous number 10 shirt at Juventus and revealed upon his arrival in Italy that he had rejected interest from AC Milan.
The move ends Tevez's seven-year stay in England after spells with West Ham United, Manchester United and City.
Tevez's departure leaves City with only two recognised strikers in the squad with Sergio Aguero and Edin Dzeko remaining at the Etihad Stadium.