Chiellini tore anterior cruciate ligaments in his right knee in training last Friday and missed Juventus’ game against Napoli on Saturday as a result.
Chiellini was initially named in the Italy squad by Roberto Mancini for matches against Armenia and Finland in the EURO 2020 qualifiers but his place has now been taken by Lazio’s Francesco Acerbi.
The 35-year-old played in Juventus’ first game of the season away to Parma and scored the only goal in a 1-0 win.
Chiellini had an operation in Austria on Tuesday, with the prognosis revealing that he will be unavailable until March 2020 at the very least.
"This afternoon, Giorgio Chiellini underwent surgery to reconstruct the anterior cruciate ligament of the right knee," a statement on Juventus' website read.
"The intervention, performed at the Hochrum clinic in Innsbruck by Professor Christian Fink in the presence of the Juventus Club Doctor, Dr. Tzouroudis, was perfectly successful.
"The expected recovery time is around six months."
Matthijs de Ligt, who joined Juventus from Ajax Amsterdam in the summer, will be the likeliest beneficiary of Chiellini’s absence.
Chiellini has subsequently been left out of the Bianconeri’s UEFA Champions League squad for the group stages, where they have been drawn against Atletico Madrid, Bayer Leverkusen and Locomotiv Moscow, but can be reinstated when the knockout stages get underway.
