Despite being out of favor at Real Madrid, it would be a big surprise should he arrive at Old Trafford. Reuters

Having already made one superstar signing this summer in Robin van Persie, Manchester United have been linked with an unlikely bid for another, with speculation that they could look to bring Kaka on a season-long loan deal.

The Real Madrid attacking midfielder is known to be available this close season having struggled to earn a regular place in the first team under Jose Mourinho. The Brazilian, a former World Player of the Year, was an unused substitute as Real began their La Liga season with a 1-1 draw at home to Valencia on Sunday.

Kaka's reported wages of £250,000 a week could well prove a stumbling block to any move, however. That is not the only reason why Old Trafford appears an unlikely destination for the 30-year-old. Since his record-breaking close-to-£60-million transfer from Milan in 2009, Kaka has suffered serious injuries which have left him lacking the fleet of foot that made him one of the world's greats.

Added to that is the fact that United have no need for a player in his position. The signing of Robin van Persie already leaves manager Sir Alex Ferguson with a dilemma of how to integrate new attacking midfield signing Shinji Kagawa into the side.

United are also set to add to their attacking options even further with the signing of Angelo Henriquez. The 18-year-old Chilean was spotted completing a medical in Manchester last week. While no deal has been confirmed by United, Henriquez's club, Universidad de Chile, have revealed that the signing will happen.

"Angelo Henriquez will join Manchester United this month," read a club statement.

"The player is physically and mentally prepared to take this determining step in his career."

United are known to have had a first option arrangement on the forward and Universidad chairman, Jose Yuraszcek claimed that the Red Devils were eager not to wait any longer before bringing Henriquez to the club.

"Manchester United's representatives told us that it was fundamental for them to take him now," he said.

Despite the competition for places up front at United, Henriquez believes that he will get his opportunity.

"If I go to Manchester United, it is to play," he told El Mercurio. "Going to one of the best teams in the world is a big challenge. The club has to play in more competitions, so I will have the opportunity to play minutes for the first team."

Henriquez is not the only player soon to have his arrival at United finalized, with the club also having ended their search for a left-back. Vitesse Arnhem's Alexander Buttner has been photographed in Manchester reportedly before undergoing a medical at United, according to the Daily Mail.

It's claimed that the 23-year-old is set to sign five-year contract with a £3.9 million fee agreed between the clubs.

While Buttner was in the Netherlands' preliminary squad for Euro 2012, United's decision to recruit him to provide back-up to Patrice Evra is a surprise-even to the player himself.

"If you had told me one week ago that I would be training with and playing for the same team as Robin van Persie, I would have sent you to a mental home!" Buttner said, according to the Mail.

"This is crazy stuff, beyond all my dreams. I am looking forward to this challenge so much. I am so proud and so glad that it has worked out like this.

"I'm so glad that it has happened and everything has turned out like this. This is really a dream come true."

United could also strengthen their defensive options with a move for Saint-Etienne youngster Kurt Zouma. French publication L'Equipe reports that United, as well as Chelsea, had scouts watch the 17-year-old central defender in action against Toulouse on Saturday.