Sir Alex Ferguson
Sir Alex Ferguson has been left frustrated by Paul Pogba, but remains optimistic about strengthening his squad for next season. Reuters

Despite two transfers already being completed, Manchester United fans can still expect an exciting summer of transfer activity ahead as the club looks to return to the top both at home and in Europe.

Sir Alex Ferguson has confirmed, in an interview with MUTV, that he has further deals in the pipeline.

Yes, there's a possibility, he said. We're working on one or two things but there's nothing really to tell you to be honest.

We always try to get our work done at the end of the season-we spent a good deal of time sorting the deal with Shinji and we'd agreed a deal with Nick Powell before the play-offs which was a good move by us because the boy had an outstanding final at Wembley.

When you don't get deals done immediately and you're negotiating with a club over a long period, then you can't expect to just snap your fingers and get it done.

One of those players coming in looks set to be a central midfielder, with speculation continuing in recent days over United's hunt for reinforcements in that crucial area of the side. The Sun leads with an exclusive on Tuesday claiming that the United have become frustrated with what they see as Tottenham's excessive demands for Luka Modric.

As a result, United have reportedly firmly turned their attentions toward Portuguese midfield Joao Moutinho. According to the Sun, a £25 million offer is being prepared. At a full £15 million less than Tottenham are said to be asking for Modric, Ferguson may feel that the Porto star represents better value for money.

After helping his club to back-to-back Portuguese Liga titles, Moutinho, 25, further enhanced his reputation with a starring role as Portugal reached the Euro 2012 semifinals.

Tottenham and Chelsea are also said to be monitoring the former Sporting Lisbon player.

There could be a further alternative on the horizon with reports that Benfica may be prepared to listen to offers for Axel Witsel this summer. United have been linked to the Belgian international for several months after he played a key role in helping the Portuguese side to the Champions League quarterfinals.

Although the 23 year old arrived from Standard Liege just last summer, Dutch publication De Telegraaf reports that Benfica could be willing to allow him to leave if a bid of £20 million is forthcoming.

Witsel is more of an all-round player than either Modric or Moutinho and, while he may not as proficient a passer, is known for his robust tackling.

Chelsea and Real Madrid are also said to be interested in his signature.

United have also been linked with a deal for Inter goalkeeper Julio Cesar. With David de Gea now seemingly established, following a difficult start to his Old Trafford career, there would seem little requirement for the 32-year-old Brazilian international. But, La Gazzetta dello Sport says that there is interest there and Inter could be prepared to do a deal given their interest in Udinese stopper Samir Handanovic.

Though Julio Cesar could potentially offer an experienced alternative to De Gea, any deal still appears unlikely.

One player that definitely won't be plying his trade at Old Trafford next season is Paul Pogba. After months of speculation, Ferguson has confirmed that the young French midfielder has signed a contract with Juventus, much to his dismay.

Pogba signed for Juventus a long time ago as far as we're aware, Ferguson told MUTV.

It's disappointing. I don't think he showed us any respect at all. To be honest, if they carry on that way, they're probably better doing it away from us.