Romero collided with Diego Costa when the Spain striker opened the scoring in the 12th minute of the contest in Madrid, and – having initially tried to play on – was replaced by Willy Caballero as Argentina went on to suffer a humiliating 6-1 defeat.
The 31-year-old, who was starting opposite David de Gea, the man he plays understudy to at Old Trafford, consequently underwent tests that ruled out major damage.
A statement from Argentina read: "Sergio Romero suffered a trauma to his right knee.
"The tests done have ruled out any serious bone or ligament damage."
It remains to be seen if Romero will be available for United's squad to face Swansea City on Saturday.
Romero has made nine appearances for United this season in all competitions, although he has yet to feature in the Premier League.
Since joining United in 2015 on a free transfer, Romero has played 37 times for the club, wiith the bulk of his outings coming in cup competitions or Europe.
Earlier this month, ahead of United's FA Cup quarter-final win over Brighton, in which Romero kept a clean sheet, he spoke of how he prepared for games and ensured his mindset was right, despite his lack of regular game-time.
“I never leave anything to chance. I always work hard to be ready for when my chance comes.
“My priority is being ready 100 per cent, in good shape both physically and mentally, because I'm not just fighting for many things for my club.
"I'm also fighting for many things at international level, so I'm someone who has his head in the right place to perform well.”