Robin van Persie
Robin van Persie faces an anxious wait to discover the nature of the ankle injuryGetty Images

Manchester United striker Robin van Persie will face a scan on the ankle injury that forced him off during the Premier League defeat to Southampton, manager Louis van Gaal has confirmed.

Van Persie was replaced by Ander Herrera after 61 minutes following a challenge on Jose Fonte during the 1-0 defeat at Old Trafford, limping off the pitch.

The 31 year old will be assessed to discover the extent of the problem, which could keep him out of United's trip to Queens Park Rangers on Saturday 17 January, but the Netherlands international will now not attend the Ballon d'Or Gala in Zurich, where he is nominated for the goal of the year award.

Defender Luke Shaw and record signing Angel Di Maria were also replaced during the game on Sunday 11 January, with Tyler Blackett and Marouane Fellaini coming on, but Van Gaal clarified their withdrawal was precautionary.

"Shaw was not injured but he needs match rhythm," the Dutchman said. "Also Di Maria, he is not injured but he needs match rhythm. That is why I had to change.

"Of course, we have players who are coming back but then we also need match rhythm. It is not so simple to play in the Premier League, so I have to adapt to the circumstances."

Injury to Van Persie, who has scored eight Premier League goals in 20 starts this season, was accentuated by Radamel Falcao's omission from the United matchday squad after James Wilson was preferred to the Colombian forward.

United failed to muster a shot on target throughout the 90 minutes as the Saints recorded their first league win at Old Trafford for 27 years through Dusan Tadic's goal but Van Gaal attributed the loss to the visitors' dogged defensive display.

"They were defending well," he said. "You have always got to take into account that the opponent can play well.

"They defended well, [they had] good organisation, but they came for a draw I think and they go away with a victory. That is disappointing."