The 24-year-old, who won at Melbourne Park and Wimbledon this year, was instrumental in Italy's successful Davis Cup defence in 2024 in Spain but said on Monday he was sitting out the Final 8 set to take place in Bologna from November 18-23.
He will be in Turin a week before the Davis Cup to defend his ATP Finals title, where world number one Carlos Alcaraz has also secured his place in the season-ending championship.
"It wasn't an easy decision, but after Turin, the goal is to get off on the right foot in Australia," Sinner told Sky Sport Italy. "It may not seem like it, but a week of preparation during that period can make all the difference.
"We won the Davis Cup in 2023 and 2024, and this time we decided this with my team."
Next year's Australian Open, the opening Grand Slam of the season, runs from January 12-26.
Sinner beat Alcaraz to win the lucrative Six Kings Slam exhibition event in Riyadh on Saturday and will next be in action at the Vienna Open, which he won in 2023.
"We are working hard on my serve. I am fortunate to be able to work continuously with the best team possible," he said. "I now have some very important tournaments coming up, in Vienna, Paris and Turin."