Grant has spoken out on the future of the France international after he was dropped from the team against Manchester City, having struggled to find his best form.
Grant is adamant that the speculation is well wide of the mark as Villa have no plans to offload N'Zogbia, who only joined them in a £9million deal from Wigan in the summer,
Grant told the club's website: "You know what football's like, people talk about somebody moving every day. I think it was Benty last week, now it's Charles. I don't know who it will be next!
"People are talking about players going here, there and everywhere. Sunderland must have a few bob left if they are going to try and buy Charles!"
Grant is also confident that 25-year-old N'Zogbia will soon rediscover the form which persuaded the club to part with big money for his signature.
He added: "We feel in the last few weeks that Charles is starting to get there. The boys appreciate his talent because they see it on the training ground. That's why we're confident that there's a lot more to come from him."