The Argentinian playmaker looks set to leave City after the club reached an agreement with Brazilian outfit Corinthians.
Vieira is full of praise for the role the influential Tevez has played in City's development over the past two seasons, but expects the club to quickly move on.
Vieira, who announced his retirement last week, said: "It is never easy to lose players like Carlos Tevez.
"In the last two years he has been fantastic for the football club, scoring goals.
"The club has grown that fast and Carlos has made a huge contribution to it, like all the players.
"But in football, it is not the first time a big club has lost a big player.
"I believe we can still achieve our targets and we will still have a really competitive team.
"The players will take more responsibilities on their shoulders and that will make them better players.
"If Carlos does leave we just have to wish him good luck and say thank you for everything he has done for the football club."
Tevez has often voiced his unhappiness with life in Manchester and spoken of his desire to be closer to his family in Argentina.
City turned down a ?40million bid from Corinthians last week and were thought to be holding out for ?50million for a player who scored 20 goals in the Barclays Premier League last season.
However, speaking on the club's pre-season tour of North America, manager Roberto Mancini told Sky Sports News: "We have an agreement with Corinthians but Carlos now is still a City player."
Source: Team Talk
Source: Team Talk