Sanchez is yet to make a competitive appearance for the Gunners this season due to an abdominal strain and is expected to miss Saturday's trip to Stoke City.
However, the dynamic forward has been deemed fit by national team manager Juan Antonio Pizzi for the two matches on August 31 and September 5.
Capped 115 times at international level, Sanchez is Chile's all-time leading goalscorer and appeared in all five matches as La Roja reached the Confederations Cup final in July.
"The information we have is that he is available," Pizzi said on Thursday.
"He will not have problems getting to the qualifying date."
Manchester City and Paris Saint-Germain have been credited with an interest in Sanchez but Arsenal manager Arsene Wenger says he is prepared to make a "financial sacrifice" by losing him on a free transfer at the end of his current deal.
The 28-year-old has less than a year remaining on his contract at Emirates Stadium, having joined from Barcelona in July 2014.
Chile currently sit just inside CONMEBOL's automatic qualification spots, one point ahead of fifth-placed Argentina with four matches remaining.
Goalkeepers: Claudio Bravo (Manchester City).
Defenders: Paulo Diaz (San Lorenzo), Osvaldo Gonzalez (Toluca), Mauricio Isla (Fenerbahce), Eugenio Mena (Sport Recife), Enzo Roco (Cruz Azul).
Midfielders: Charles Aranguiz (Bayer Leverkusen), Marcelo Diaz (Celta Vigo), Felipe Gutierrez (Internacional), Pablo Hernandez (Celta Vigo), Gary Medel (Besiktas), Francisco Silva (Cruz Azul), Arturo Vidal (Bayern Munich).
Forwards: Nicolas Castillo (UNAM), Fabian Orellana (Valencia), Edson Puch (Pachuca), Alexis Sanchez (Arsenal), Leonardo Valencia (Botafogo), Eduardo Vargas (UANL).