Ángel di María is expected to be announced as a Manchester United player imminently after undergoing a medical ahead of the completion of his transfer from Real Madrid in Manchester on Tuesday. The Argentina international is set to cost United around £60 million to take the club’s summer spending to a mammoth £135 million, and it may well not end there.

This summer has long been earmarked by the club as one where significant investment in the squad was required following a disastrous seventh-place finish last season. Luke Shaw (£30 million) and Ander Herrera (£29 million) were both identified as targets under David Moyes before Louis van Gaal arrived and signed off on them. Earlier this month, defender Marcos Rojo was snapped up from Sporting Lisbon for £16 million to help fill the void left by the departure of experienced defensive trio Rio Ferdinand, Nemanja Vidić, and Patrice Evra.

Doubts persist about how Di María will fit into Van Gaal’s currently favored 3-4-1-2 system and whether his arrival will yield a change in approach, but the signing adds some gloss to a transfer window that had again started to become hugely frustrating. Still, despite the huge money spent, United remain short in key areas; none more so than in central midfield.

Against Sunderland on Sunday, Van Gaal started with an unconvincing midfield partnership of Tom Cleverley and Darren Fletcher before being compelled to bring on Adnan Januzaj in an unfamiliar role. Following the match the former Netherlands coach lamented his lack of midfield options, admittedly in large part caused by injuries, while also intriguingly namechecking Arturo Vidal. The Juventus midfielder has been linked with a transfer to Old Trafford for several months, with various reports now claiming that interest could be stepped up following the capture of Di María.

The Independent is one of those sources, with the British broadsheet reporting that United are now open to negotiating with Juventus for the Chile international. It has perhaps been baffling that United have not more strongly pursued a player who has helped Juventus to three-straight Serie A titles and has established himself as arguably the world’s best all-round midfielder. It is no exaggeration to say that Vidal’s arrival would transform United’s midfield from an area of weakness to one of immense strength.

It has long been believed, though, that the major issue holding up any progress on the transfer was Manchester United’s concerns over Vidal’s knee injury. The 27-year-old underwent an operation in May, and, despite playing at the World Cup, was clearly not fully fit. According to The Independent, United are so hesitant about the long-term impact of the injury that they intend to introduce substantial performance-based conditions into Vidal’s contract.

ESPN has a similar story and reports that discussions about such a contract have already taken place between Vidal and United. It would still be a surprise were a player of Vidal’s standing to accept a contract with a relatively minimal basic wage, while United would also face a challenge to negotiate a fee with Juventus that both clubs considered reasonable.

There have been suggestions that, were Vidal not to arrive, Manchester United would target Milan’s Nigel de Jong as a backup. But, while it does not rule out Van Gaal targeting a player he worked with during this summer’s World Cup, The Independent, at least, does not think that the former Manchester City midfielder is currently on the agenda at Old Trafford.

United may instead target another player to impress with the Netherlands at the World Cup, Daley Blind. Reports in the Netherlands on Monday night even suggested that a deal had been struck for a player who would provide an option at center-back, left-back, left wing-back, as well as at arguably his best position in midfield. However, the Ajax man’s agent has stated that there has been no contact form Manchester United about a transfer.

“At this moment Manchester United have not been in touch with me or Ajax about Daley and I’m not sitting here waiting for the call,” Rob Jansen told Talksport.