N'Zogbia is expected to complete his move to Villa Park before the end of the week, and McLeish expects the Frenchman's arrival to be the last of the summer.
"You can never say never but at the moment if we get N'Zogbia, which is looking good, then it's unlikely we will do anything unless there's more trading with the players we already have in the squad," McLeish said after Villa's 1-0 win over Blackburn at the Barclays Asia Trophy on Wednesday.
"At the moment we don't plan to do any more business, I believe we've got some great young players and we've got one or two sleepers in there that could emerge.
"I know Ashley Young's boots are big ones to fill but there are one or two players that could emerge as a result of Ashley leaving the club."
Club owner Randy Lerner has one eye on UEFA's Financial Fair Play regulations, which will be implemented based on clubs' financial results from the upcoming season and the 2012-13 campaign.
McLeish said: "We're watching the wages don't spiral out of control. Even bringing in free transfers, everybody thinks they don't cost you anything but they could be 50-60 grand a week in wages and it just escalates the wage bill out of all proportion.
"Randy Lerner has already stated that he wants to keep it tighter and work within a means and that's normal, especially with 2013 coming up, and I believe a lot of clubs will follow suit.
"We have a good squad, I have to pay respect to the lads that are already there, they're on big wages and I can't just discard them."
The game itself proved a keenly-contested affair, with Darren Bent's clinical finish ultimately the difference between the two sides.
"I said that before the game that because it was a Premier League game there was a little bit of an edge, a few meaty tackles but I was pleased with the performance of the lads in intense heat and humidity," said McLeish.
"I take a lot from that game in terms of seeing my players and creative moments like Barry's fantastic cross for Bent's winner and also some really solid defending, when we had to we were up to the mark."
The Scot deployed striker Gabriel Agbonlahor in a deeper role with Bent and Emile Heskey also in the line-up and was pleased with what he saw.
"I thought he did very well. He was a threat, got into some good positions and there's a lot of food for thought in that position," he said. "The reason we played that way was that Blackburn were loaded in midfield and we didn't want to get overpowered and Gabby did a good job.
"We'd like to think that we could play guys like Gabby and Benty, both England players, together every week but that won't happen, it'll be horses for courses. It's a long season and you can't always play 4-4-2."