The star striker scored in Arsenal's 3-1 Premier League defeat to West Brom on Sunday (AEDT) but had to be substituted in the second half after finding himself on the wrong end of a heavy James McClean tackle.
Gunners manager Arsene Wenger delivered a grim initial prognosis, claiming the forward's ankle had been left in an "absolutely terrible state".
But the 28 year-old former Barcelona player has nevertheless travelled to South America for his country's matches away to Argentina and at home to Venezuela.
A report in El Grafico claims a member of the Chile national team's medical staff has declared that Sanchez is likely to be fit to take on Edgardo Bauza's side in Buenos Aires on Friday (AEDT).
Chile occupies the fourth and final automatic qualifying spot in the CONMEBOL group.
Argentina is a point below it in fifth place, a berth which would require the mighty Albiceleste, beaten finalist against Germany at the previous World Cup in Brazil in 2014, to suffer the indignity of negotiating the inter-confederation play-offs if it is to reach the finals in Russia next year.