Day's wife, Ellie, gave birth last month to the couple's second child, Lucy. Day had planned to play both this week at the Hero World Challenge and next week in Naples, Fla., but has now withdrawn from both events for more time at home.
"Regrettably, I am withdrawing from the 2015 Franklin Templeton Shootout to stay in Ohio with my family and newborn daughter, Lucy," Day said in a release. "Our win in 2014 was the beginning of an incredible run for me, and I hope I can return to compete in the event in the near future."
Day will be replaced in the field by Chris Kirk, who will team with Tringale.
The announcement means that a breakthrough year on the course for Day is now over. The Aussie won five times on the PGA Tour, including the PGA Championship, and reached the No. 1 spot in the world rankings after his win at the BMW Championship. He last teed it up at the Presidents Cup, missing out on some of the bigger events in Australia in recent weeks because of his wife's pregnancy.
The Franklin Templeton Shootout will be held Dec. 10-12 at Tiburon Golf Club. Featuring 12, two-man teams, the event format includes one day of scramble, one day of modified alternate shot and one day of better ball.