Manchester United are the only club to make a firm approach for Borussia Dortmund striker Robert Lewandowski, according to the player’s agent.

The Poland international has been linked with a move to Old Trafford since last summer, when it is believed they expressed interest before signing Robin van Persie. In recent weeks, though, there has been strong speculation that Lewandowski had already agreed terms with Bayern Munich.

The 24-year-old’s agent, Cezary Kucharski, was coy about Bayern’s potential interest, but suggested that United remained his likely destination.

“Many clubs follow the player, but really it is only specifically Manchester United,” he said , according to TalkSport.

"Bayern Munich? I know something, but no further details. In June we'll see, but [a move to] Juventus is just a rumor. Nobody at the Italian club has talked to me."

Lewandowski will have just a year remaining on his contract this summer and it is widely believed that Dortmund will be forced to sell the prolific front man, in order to avoid losing him for free the following year.

Following Manchester United’s Champions League first-leg draw with Real Madrid in midweek, midfielder Anderson has made a surprising declaration to Brazilian outlet Globo Esporte that he has tried without success to leave the club on several occasions.

A mixture of injuries, poor form and doubts over his fitness have seen the Brazil international fail to establish himself at Old Trafford since joining the club from Porto in 2007. His latest comments, when asked if he could return to Portugal, that he is keen on a move are unlikely to help him move further into Sir Alex Ferguson’s plans.

“What can I say? I have three more years of contract, I have tried to leave many times  and never succeeded to do so,” he said, according to Sky Sports.

Another 2007 signing, Nani, has also been the source of consistent speculation linking him with a departure from Old Trafford. Although Wilfried Zaha is already set to arrive in the summer, and could be a potential replacement for the Portugal international, United are also said to have their eye on a more high-profile winger.

The Daily Express reports that Barcelona’s Alexis Sanchez could well be on their radar for the summer. The Chile international has had a difficult season at the Camp Nou, looking short of confidence, having only scored his first league goal of the season last weekend.

According to Spanish publication Sport, Sanchez is also interesting Juventus and could be available for €26 million (£22.4m).

Sanchez was heavily linked to United before eventually joining Barcelona from Udinese in the summer of 2011.

According to Metro, Lille left-back Lucas Digne could also be on Manchester United’s agenda in the close season. The report claims that Ferguson and the club’s scouts have made frequent checks on the 19-year-old in recent times.

Now it is believed that chief scout Martin Ferguson has urged his brother, Alex, to get a deal done this summer. It is also suggested that the France Under-19 international could be available for £7 million.

A move may be unlikely, though, with Digne having only signed a new contract in December to keep him at the club until 2017.