Chile have announced that the in-form Arsenal forward, who has scored eight goals in 15 matches for the Gunners this season, has suffered a "low-grade muscle injury".
Reports in Chile suggest the 27-year-old picked up the injury in training and it looks likely that he will play no part in Thursday's match against Colombia in Barranquilla.
It also remains to be seen if Sanchez will be able to feature in next Tuesday's home match with Uruguay, with the Chile Football Association confirming his recovery is being monitored.
A statement on www.anfp.cl read: "The medical staff of the Chile national team inform that Alexis Sanchez has a low-grade muscle injury.
"The player will remain in Santiago, under treatment and being evaluated for Chile's match against Uruguay."
Chile are fifth in their World Cup qualifying section with 16 points from 10 games, five points behind leaders Brazil.
Arsenal's next fixture is the Premier League trip to Old Trafford to face Manchester United on November 19.
Source : PA
Source: PA