Argentina's Angel di Maria will undergo a scan on his injured thigh after the midfielder hobbled out of their quarter-final win over Belgium on Saturday, with local media suggesting his World Cup could be over.
Di Maria was forced off after 33 minutes of their 1-0 win at the Brasilia national stadium.
The Real Madrid player, who scored the 118th minute winner against Switzerland in the last 16, was replaced by Enzo Perez on Saturday.
Perez is likely to remain in the team for their semi-final on Wednesday against either the Netherlands or Costa Rica in Sao Paulo should Di Maria be ruled out.
Argentina coach Alejandro Sabella said the player would visit doctors on Sunday.