Angel di Maria has picked up a suspected thigh injury in the first half of Argentina's World Cup quarter-final with Belgium.
The Real Madrid midfielder was fit enough to walk from the field, but looked to be in some discomfort when being replaced by Enzo Perez just past the 30-minute mark in Brazil.
Argentina currently lead 1-0 at the interval courtesy of an early strike from Napoli forward Gonzalo Higuain.
Should the South American outfit progress, they would face either Netherlands or Costa Rica in the semi-finals of the competition.
The first semi-final, meanwhile, will pit the hosts Brazil against Germany on Tuesday.
