Angel di Maria
Manchester United midfielder Angel di Maria suffered an injury during Argentina's Copa America final loss against Chile on Saturday, 4 July Getty

Manchester United star Angel di Maria limped off with what reportedly looked like a hamstring injury during Argentina's Copa America final loss against Chile on Saturday, 4 July.

The Argentine midfielder was substituted inside the first half-hour after he pulled up while making a mazy run through the Chilean midfield. According to United's official site, it looks to be a hamstring strain.

This will be a cause for concern for Louis van Gaal with the Premier League season set to get underway in just over a month's time, with the Red Devils opening their campaign with a crucial game against probable top four contenders Tottenham Hotspur.

The 20-times English champions begin their pre-season training on Monday, and even though Di Maria would have been afforded a break due to his participation in the Copa America, this injury will be a blow for the former Real Madrid star, as it will curtail his preparations for the new season following last season's struggles.

The 27-year-old midfielder started life in the Premier League brightly, but later struggled for form and fitness, which eventually led to the Argentine losing his place in the team during the latter part of the 2014/15 campaign.

Di Maria failed to score in the Premier League since his goal in early October against Everton, and his last start for United came during their FA Cup quarter-final loss at the hands of Arsenal in February, a game in which the Argentine was sent off for assaulting the referee after already having been booked.

According to the Daily Mail, the injury sustained by the midfielder could reportedly see him miss United's entire pre-season preparations, which is likely to hamper his start to the campaign yet again after having missed last season's preparations due to Argentina's appearance in the finals of the 2014 World Cup, a game he also missed through injury.