Carlos Vela is set to miss Mexico's final Group A game against Uruguay and could be doubtful for a potential second round clash.
Mexico still have work to do to secure their place in the last 16 but Vela will be unavailable for the clash with Uruguay on Tuesday.
The Arsenal striker suffered a hamstring injury in Thursday's 2-0 victory over France and is facing 'up to ten days' on the sidelines, according to Mexican officials.
If Mexico book their spot in the second round, Vela would then be struggling to recover for their next match, which would take place on either Saturday 26th June or Sunday 27th June.
Mexico are on the verge of qualifying and a draw with Uruguay would take both teams through at the expense of France and South Africa.
Conspiracy theories have been dismissed, with Mexico knowing that a point in their final game would leave them second in Group A and almost certainly set up a meeting with Argentina in the last 16.
Mexico are therefore keen to finish top of their group, although veteran striker Cuauhtemoc Blanco insists he would not be worried facing Argentina.
"We don't have a problem with playing Argentina. They have many good players but we're not afraid of them," the 37-year-old told reporters.
Speaking about Argentina's dangerous forward line, Blanco added: "We would treat them as equals."
Blanco also urged caution ahead of the Uruguay encounter, saying that Mexico had to stay focused after an impressive performance against France.
"We haven't won anything yet," said Blanco, who brought his international goal tally to 39 from the penalty spot in Polkwane.
"We know we're coming up against a tough team but they have weaknesses and we have to find them and make the most of them."