Manchester United target Kevin Strootman appears to have opened the door for a summer move by inviting clubs to make a firm approach.

The PSV Eindhoven midfielder has been consistently linked with both United and Italian giants AC Milan for over a year and his agent, Chiel Dekker, has previously suggested that there could be movement this summer. Dekker also claimed that United had been in contact and that his client favored a move to the Premier League.

Strootman, 23, has already captained the Netherlands and is the type of box-to-box midfielder that United have arguably lacked since Roy Keane. There have recently been reports that United’s midfield could get an overhaul this summer, with doubts about the future of Anderson, Paul Scholes and Darren Fletcher.

Strootman is aware of the interest being shown in him and has encouraged clubs to make an offer in the summer.

“Every transfer window there are clubs that are interested, but a club must speak to me,” he said, according to TalkSport.

Another long-time Manchester United target is also involved in recent speculation. According to the Daily Mail, United boss Sir Alex Ferguson is monitoring Alexis Sanchez’s situation at Barcelona closely with a possible summer move in mind.

It is believed that the Chilean forward rejected a move to Old Trafford before signing for Barcelona in a big-money transfer in 2011. But Sanchez has struggled this season, scoring just twice in La Liga to lead to talk of a possible departure. Juventus, Internazionale and Arsenal have also been mentioned as potential destinations.

With speculation continuing over the future of Nani and Antonio Valencia and Ashley Young both enduring disappointing campaigns, a new winger may be on the agenda for Ferguson in the close season, despite having already signed Wilfried Zaha.

Manchester United could also make a long speculated move for Christian Eriksen this summer, with the attacking midfielder continuing to waver over signing a new contract at Ajax.

The Denmark international has long been tipped to be a leading star, with the likes of United, Liverpool and Tottenham all thought to be interested.

Eriksen’s current contract runs until the summer of 2014, meaning that Ajax would likely be forced to sell the 21-year-old if he fails to pen a new deal this summer.

“I have not got a definite offer of an extension,” Eriksen told Danish publication Sporten.

"But my agent has had some talks with the club about it. How it's going to look after the summer, I do not know. 

"I do not know if I'm playing at Ajax after the summer."

There has been recent speculation too suggesting that Manchester United are keen on young Paris Saint-Germain midfielder Marco Verratti. The 20-year-old only moved to the French capital from Italian side Pescara last summer and the playmaker has been a regular for Carlo Ancelotti’s side.

There has been speculation that Ancelotti could be dismissed, but Verratti’s representative Donato Di Campli has said that his client’s future is not tied to the man who brought him to PSG.

"I know that Paris Saint-Germain believed in the player [when they signed him last year] and he is having a great time in Paris,” Di Campli said, according to TalkSport.

"I think it will be very difficult for him to move away from Paris.

“Marco's future is not linked to Ancelotti's future. Marco is tied to a major project which sees him as the pivot of a team which is fighting for top spot in France and in the Champions League."