The Frenchman's comments come after Manchester City's most recent bid, which is understood to total around £40m when including add-ons.
Liverpool have so far refused to do business with City over the England international, who has two years remaining on his current contract. The Anfield hierarchy value the 20-year-old - who has turned down a new £100,000-a-week contract at Liverpool - at £50m.
While some have criticised that valuation, Vieira is a fan of the youngster.
"I think if you go down and ask 10 people what they think about him, I think nine would give you a positive answer," Vieira told ESPN FC at an event in New York for Western Union's PASS initiative.
"I would be part of the nine people because he's shown how good he is, how well he's been doing at Liverpool.
"If he is in the market, not just City would be interested in him.
"But that's the first team and I'm not part of the first team, I work with the academy so I'm just giving you my opinion."
Vieira also believes the loss of their Premier League title honour to Chelsea last season should be viewed in context.
"The target of the football club is to always try to win the Premier League title. You only have one team who can win it," he added.
"Chelsea won it last year, so that means United, City, Arsenal and Liverpool were not going to be happy, but I think what is important is to analyse the situation and analyse what the club has achieved in the past four years.
"If you analyse the last four years, it's been more successful than anything else.
"Don't forget that four or five years ago, the club wasn't at that level.
"I think the journey of the club so far has been fantastic and you just have to look at the players we have in our squad."