Sir Alex Ferguson has said Manchester United will not go back into the transfer market before the end of the month, declaring "you can forget" the idea of Wesley Sneijder signing and masking any sense of disappointment by placing his trust in the emerging crop of young players at Old Trafford.

Ferguson had made signing a new central midfielder a priority this summer but the Premier League champions are resigned to Samir Nasri joining Manchester City from Arsenal and, as the Guardian revealed on Thursday, have let it be known that exploratory talks about Sneijder's potential availability at Internazionale have amounted to nothing.

United's official stance is that the Sneijder deal is now finished and Ferguson insisted he is happy to begin the season with his current squad and, as well as highlighting Tom Cleverley's impressive performance in the Community Shield, he reiterated his faith in Michael Carrick, Anderson and Darren Fletcher and talked for the first time about promoting the 18-year-old Paul Pogba to the senior team.

"When you take that roll call of players, I'm certainly not looking to add to that," the United manager said. "I've been saying that for weeks but you [the media] have all been writing differently – that I'm going to buy this one or that one. But we've said nothing, we just carry on with our business."

Ferguson was asked whether United's official briefing about Sneijder, originating from the Old Trafford boardroom, meant the club should forget about the possibility of signing the Holland international. "You can forget anyone you like," he replied. "I'm happy with the young players I've got."

At one point in the Community Shield the average age of United's team was 22 years and two months and it could go even younger if Ferguson rewards the French teenager Pogba for the "great promise" he showed for the team who won last season's FA Youth Cup.

Pogba is a tall, rangy central midfielder, signed from Le Havre at the age of 16. "We're quite positive about him," Ferguson said. "If we hold Paul Pogba back, what's going to happen? He's going to leave in a couple of years' time when his contract is finished. We have to give him opportunities to see how he can do in the first team. He's got the ability, the physique and the athleticism."

Ferguson also confirmed he would stick by David de Gea for Sunday's game at West Bromwich Albion rather than bringing in Anders Lindegaard, seven years his senior. De Gea's goalkeeping was scrutinised after both Manchester City goals last weekend but Ferguson believes it was inevitable the 20-year-old would have a few lapses. "The reason we bought him and spent £18m is the long-term view," Ferguson said. "He was unfortunate with the second goal. We didn't expect that and he won't be doing that again. But he had no chance with the first. The goalkeeper has absolutely no chance when the ball is whipped in like that. It needs only a fraction of a touch and the goalkeeper's dead."

He noted "there was no criticism" of Joe Hart after Chris Smalling had scored United's first, despite it being "exactly the same type of goal – and he's your bloody [England] national goalkeeper".

United, nonetheless, need their inexperienced players to acclimatise quickly given that they play Arsenal, Chelsea, Tottenham Hotspur, City and Liverpool in their opening nine games.

Rio Ferdinand said recently that "our enemies couldn't have picked it any better" and Ferguson is also unimpressed. "I keep saying I'll send someone down to watch that," he said. "It's a tough start. The only way you can handle it is to have everyone fit in the early part of the season."

United, though, have injury doubts about Patrice Evra and Carrick, while Fletcher and Antonio Valencia are at least one more week away from returning and Javier Hernández is still being monitored closely after the concussion he suffered on 26 July. Ferguson reported that the Mexican was still "10 days from appearing in any football" and "should be 100 per cent in possibly four weeks."