Angel Di Maria and Marcos Rojo are set to miss the start of Manchester United's season, and potentially the crucial Champions League play-offs, after they reached the final of the Copa America with Argentina.

The duo both played in all six of Argentina's games at the tournament in Chile, culminating in the final which went to extra-time before the hosts won the competition in a penalty shoot-out.

Speaking before the tournament, Manchester United manager Louis van Gaal admitted that should Argentina go deep into the tournament, it was likely his players would probably miss the beginning of the new campaign.

"Yes, of course [they may miss the start of the season]”, Van Gaal said in a press conference.

“They need, as the other players do, holidays. When they are playing in the final – and that is possible with, for example, Argentina – then they are again late in our preparation.

“That’s not so good for Manchester United, but I hope they shall play in the final because that’s great for them."

Manchester United manager Louis van Gaal (Getty Images)

In the case of Di Maria, it's possible that he may not be available anyway due to picking up a hamstring injury during the final in Santiago that forced him off in the first half. The extent of the injury is not yet known.

Angel Di Maria leaves the field in the final of the Copa America (GETTY IMAGES)

The rest of the Manchester United squad are due to report for training on Monday before they depart on their pre-season tour of the United States on 13 July.

Their season starts with a tricky fixture at Old Trafford against Tottenham on 8 August. If Di Maria and Rojo were unavailable for all of August, they would miss Premier League games against Spurs, Aston Villa, Newcastle and Swansea.

Perhaps more of a concern could be their absence from the Champions League qualification play-off matches. United will play the first leg on Tuesday August 18 or Wednesday 19 August and the second leg will be staged on 25 or 26 August with the winner progressing to the group phase of Europe's elite competition.