David Moyes has said Manchester United are making efforts to sign several players and is confident they will be able to add to their squad before the end of the transfer window.
Guillermo Varela, the 20-year-old right back from Uruguay, remains the only addition to the United squad this summer.
While Moyes has identified central midfield as a problem area in his squad, United have so far failed with two bids to land Cesc Fabregas from Barcelona, and had earlier missed out on Thiago Alcantara, who opted to move to Bayern Munich.
Moyes is now believed to have turned his attentions to prising Marouane Fellaini from his former club Everton, although it has emerged that the midfielder's release clause has expired.
Another bid for Fabregas is now rumoured to be in the offing, despite the player announcing he has no intention to leave Barcelona this summer. With Barcelona set to play four league games before the end of the window, United are reportedly hopeful of exploiting any doubts Fabregas has over his prospects of playing regular first-team football this season.
There have also been claims United are pursuing Real Madrid's Luka Modric.
Moyes, speaking at the Premier League Season Launch at Bacon's College in Canada Water, told Sky Sports News: "I'm confident we'll have players in before the start. We're involved in several players we're looking at and that will continue.
"Will we get them before the deadline? I hope so, but we're working very hard to do so. It was always going to be a difficult window for me personally. I joined on July 1, which has given me a short period.
"It's never the same until you've worked with the players, but we've got a great group of players -- they won the Premier League last year."
Moyes also reiterated his stance that Wayne Rooney is not for sale, despite Chelsea lodging several bids, and said he could be in contention to play a part in United's season opener against Swansea on Saturday.
Rooney completed 67 minutes of England's 3-2 win against Scotland at Wembley on Wednesday night, despite injury keeping him out of recent pre-season friendlies for his club, and Moyes, acting as a pundit for ITV, had said his performance "bodes well" for United.
On Thursday, the Scot added: "There have been no more developments -- we don't want any more developments. We've said he's not for sale. I'll see how he is [for Swansea] when we get back. We'll assess him.
"I watched the England game and I thought the 65 minutes or so he did he played well. He ran around and got himself some fitness. It's the first real outing in a competitive game he's had."