The Blues have made Aguero their latest big-money buy, splashing out ?38million to capture the Argentinian striker from Atletico Madrid.
Manager Roberto Mancini left the 23-year-old on the bench for Sunday's 3-2 defeat by Man United in the Community Shield.
But Vieira, who has taken on a football development role at City after retiring with the Blues this summer, reckons that Aguero could take the club to the next level.
"He's settling in really well," Vieira said at the Premier League season launch.
"I was surprised he didn't play in the Community Shield but he's a big asset for us.
"I think his ability is really high and I think he can bring a lot to the football club."
Mario Balotelli's attitude was again questioned after Sunday's game, with ex-United captain and new Sky Sports pundit Gary Neville branding him "a bit of an embarrassment".
But Vieira has backed the Italian striker, 21 on Friday, to show why City forked out ?24m to sign him from Inter Milan last summer.
"I think people forget how young he is," he said.
"He's a young boy and of course he's made mistakes but I hope this year he will learn from his mistakes.
"He's a really talented football player and I hope this year he's going to show everybody how good he is."
City put an end to their 35-year trophy drought by winning last season's FA Cup and after adding the likes of Aguero, Gael Clichy and Stefan Savic to their squad, Vieira reckons they are ready for bigger and better things.
"I believe we've improved since last season," he added.
"Winning the FA Cup and finishing third has given us belief, and I strongly believe that we can challenge Chelsea, United and the rest of the teams to lift the championship."
Source: Team Talk
Source: Team Talk