Alexis Sanchez has a tear in his right quadricep, according to reports in Chile, but could still risk aggravating the injury by playing in the crunch World Cup qualifier against Uruguay on Tuesday.
The Arsenal star did not travel to Colombia with his teammates and has already been ruled out of Thursday night's game in Barranquilla after picking up what his country's FA called "a low-grade muscle tear"
But Chilean newspaper El Mercurio quotes the 27-year-old as having told his circle: "It is hurting a bit but I'm fine. I'll be back for Tuesday."
Sanchez injured himself in Tuesday's training session and the forward was taken urgently to the MEDS Clinic in Santiago, accompanied by Chile's team doctor Pedro Oñate.
"The ultrasound was performed immediately. The doctors commented that with these injuries you must wait 24 hours to determine the recovery time, because the tear evolves," a source close to the situation told El Mercurio.
"If it's nine millimetres today then it could be eleven tomorrow [Wednesday]."
Alexis will undergo more tests on Wednesday but the same source said "luckily, they tell us that it's superficial and he could recover quickly."
But injury experts consulted by Chilean media weren't so optimistic about Sanchez and whether there may be repercussions to playing him in Tuesday's game - not least the threat of missing Arsenal's trip to Manchester United next Saturday.
"There is some debate over how to manage these sorts of injuries," said Mario Vera, a leading doctor.
"The traditionalists would say that something like this takes three weeks, but a modernist would say that their rehab could fix it sooner.
"One thing is clear: he won't be fit [if he plays] and there could be recurrences.
"In the case of Alexis, without knowing all of the details, it's probable that they get him ready to play in the game against Uruguay but he will go onto that field injured.
"The muscle will be more fragile, he would certainly have to play with medication to aid the symptoms."