Louis van Gaal hopes to sign the Argentina defender Marcos Rojo from Sporting Lisbon for £16m and is renewing his interest in Ángel di María after the Real Madrid forward’s proposed transfer to Paris Saint-Germain fell through. The Dutchman is also considering a move for Ajax’s Daley Blind, all of which underlines the manager’s determination to strengthen his Manchester United squad considerably in the final daysof the transfer window ahead of its close in just over two weeks time.

Rojo is a left-sided defender who can operate at centre-back, possesses considerable pace and is only 24, so fits the ideal of a Van Gaal player. The manager wants to deploy him at wing-back in his proposed 3-5-2 system or in the centre of defence. Given his considerable international experience – Rojo played all 120 minutes of the World Cup final last month and was named in the team of the tournament – Van Gaal would have no qualms regarding his ability to adapt to the Premier League. The former Estudiantes player also has experience of Russian football, having spent the 2011-12 season at Spartak Moscow.

While Rojo’s contract may contain third-party elements that can be common for players in Portuguese football, there is confidence at United that this will not be a problem. Reports in Portugal also suggested that Rojo had refused to train on Tuesday to force his transfer through.

If Rojo, Di María and Blind were landed, United’s total outlay would be more than £80m. Yet despite Luke Shaw and Ander Herrera already arriving during the window for a combined £56m, the club has set no limits on the funds available to Van Gaal. Ed Woodward, the executive vice-chairman, told the Guardian last month that United would have no concerns about breaking the world record fee of £86m paid by Real to Tottenham Hotspur for Gareth Bale last summer.

For his proposed 3-5-2 system, Van Gaal wants players of pace to operate at wing-back and the 63-year-old is conscious that Di María also has this quality, plus an attacking threat that would be a potent force against Premier League defences.

Di María had appeared certain to join PSG after the French club held discussions with Real about signing the 26-year-old but the deal broke down after the president, Nasser al-Khelaifi, said that the asking price for the 26-year-old was “too expensive”.

While Real’s demand is thought to have been more than £50m, PSG’s judgment that this was too costly has cleared the way for United to lodge a bid if Van Gaal gives the go-ahead for a player who, despite being voted man of the match in Real’s Champions League final victory over Atlético Madrid in May, is deemed surplus to requirements after the expensive arrivals of James Rodríguez and Toni Kroos, from Monaco and Bayern Munich respectively. Di María, who is in Real’s 22-man squad for Tuesday evening’s Uefa Super Cup final meeting with Sevilla in Cardiff, was named at the weekend by Van Gaal as a winger of the “highest level”. The Argentinian began the summer on the manager’s radar before PSG’s intervention seemed to have ended his interest. However, Carlo Ancelotti’s assistant, Paul Clement, admitted that Di María could still leave the club.

“Things can very quickly change – the window doesn’t close until the end of this month. But currently we have 20 outfield players and three goalkeepers, so it is not a big, big squad,” he told TalkSport.

Van Gaal may turn to Blind after seeing the deal to take Thomas Vermaelen from Arsenal collapse when Arsène Wenger demanded either Chris Smalling or Phil Jones in return.

While Van Gaal would not countenance this, and Vermaelen has since joined Barcelona, the 63-year-old had pencilled the Belgian in as the left-sided central defender in the three centre-back formation. Blind can play that role and was also used by Van Gaal as a defensive midfielder as Holland claimed third place in Brazil. The manager is short of options in this area – Michael Carrick is out for at least the next two months due to injury, leaving only Herrera, Tom Cleverley and Darren Fletcher as frontline players in the position – so Blind’s addition would strengthen his resources.

Marouane Fellaini is the club’s fourth central midfielder and, despite looking set for a move to Napoli, he could yet win a reprieve. Given the uncertainty in central midfield, Van Gaal has yet to indicate to the 26-year-old if he should leave and he could remain as emergency cover for Jones, Jonny Evans and Smalling should United also fail to add any more centre-backs before 1 September.

Fellaini, along with Robin van Persie and Adnan Januzaj, is not expected to feature in Tuesday evening’s friendly with Valencia at Old Trafford, which will be Van Gaal’s first home game as manager.Jones has become the latest United player to claim the club can win the league next term. He said: “Of course everyone wants to win the title. But we have no given right to say we should win the title every year, we have to go out there and do the business to win it ourselves. We can only do that by taking each game as it comes starting with Swansea.”