Martinez was one of United’s outstanding performers at Arsenal before being forced off in the 67th minute, when experiencing discomfort in his foot, as Harry Maguire took his place.
Reds manager Erik ten Hag said he was not sure if it was an injury, following the match, and the centre-back linked up with his country as planned.
“Licha, as you know, had an issue with his feet,” Scaloni said, ahead of the Ecuador clash. “In the last game [at Arsenal], he was in pain and went out for precaution. They have done studies and he’s well.