Ecuador will be missing key midfield man Antonio Valencia as they take on holders Brazil on Wednesday staring Copa America elimination in the face.
Valencia missed the loss to Venezuela with an ankle injury suffered in the opening group match draw against Paraguay and the medical staff feels he should not be risked.
Valencia dislocated and broke the same ankle last September during a Champions League outing.
"Unfortunately the injury has not improved to the extent that he would be 100 percent able to play," squad doctor Patricio Maldonado told reporters.
He added Valencia "still feels pain" from the injury.
"For his own good we cannot risk him. If he did turn out and got injured then we would lose him for a long time."
Maldonado indicated that his club Manchester United were being kept informed of the situation. "We are communicating over the internet, we are sending them all the tests," he said.
Only a win will see the Ecuadorians through on Wednesday.