Manchester United have turned to Argentina international Marcos Rojo as they seek to strengthen Louis van Gaal's defensive options ahead of Saturday's English Premier League kickoff. In contrast to a number of players United have approached in the current transfer window, Rojo is keen to move to Old Trafford and on Tuesday refused to train with current employers Sporting Club de Portugal in an effort to force a move through.

United have offered €20million for the defender, a sum it is understood that Rojo was told he would be allowed to leave for. Sporting, however, believe that the English club's need to reinforce is urgent enough that they can negotiate the fee upwards to a figure closer to Rojo's €30m release clause.
 
The terms of Rojo's contract with Sporting, though, stand in United's favor. The 24-year-old's “economic rights” are 75 percent owned by an investment fund, Doyen Sports, who while not directly entitled to enforce the player's sale have structured their ownership in a manner that allows them significant influence over a transfer.
 
According to a source close to the deal, should Sporting refuse to sell to United for the €20m offered, the Portuguese club will be contractually bound to pay Doyen 75 percent of the value of the rejected bid. That €15m would have to be paid within a fortnight.
 
While Sporting have been hoping to raise as much as €45m this summer by selling William Carvalho, they have yet to receive an official proposal for the Portugal midfielder, and the club's financial position is such that it would be extremely difficult to buy Rojo back from Doyen at that price.

Since his election last year, Sporting president Bruno de Carvalho has pursued a policy of reducing the club's debts while avoiding third-party ownership arrangements with funds like Doyen, who also owned a significant percentage of Eliaquim Mangala's rights before the central defender joined Manchester City this week.
 
Also a target for Southampton this summer, Rojo has spent two seasons at Sporting, operating primarily as a central defender. Used by Argentina as a left back during the World Cup, he would offer Van Gaal some flexibility of selection in the middle of the Dutchman's unconventional 5-3-2 system as a well as a more experienced alternative to Luke Shaw, the £30m England left back whose fitness he recently questioned.
 
Van Gaal wanted to keep Patrice Evra at United to share the position with Shaw and provide dressing room leadership, but lost the France international to Juventus last month. An attempt to reinforce his defense with Thomas Vermaelen ended when the Belgium international chose to join Barcelona, while Borussia Dortmund have refused to sell Mats Hummels.
 
Among a host of potential recruits pursued by United as they seek to recover the Premier League title, Toni Kroos and James Rodriguez have joined Real Madrid, Diego Costa has held to a commitment to sign for Chelsea, while Angel Di Maria's preference has been to move to Paris Saint-Germain, who can offer Champions League play this season.
 
As well as adding at least two more tactically intelligent players to his defense, Van Gaal wants to improve his midfield and on the wing. Ajax Amsterdam are aware of their former coach's strong interest in Daley Blind, and are asking €25m for the versatile Netherlands international.