Per Shams Charania of The Athletic and Stadium, Griffin is going to be out through the first week of November.
This will likely force the Pistons to play without their best player for the first 10 games of the season depending on how his recovery goes.
Griffin is coming off one of his best individual seasons in the NBA, averaging a career-high 24.5 points per game. He also added 7.5 rebounds and 5.4 assists per game while helping the Pistons earn a spot in the playoffs for the first time in three years.
The production was enough to earn his sixth career All-Star selection.
On the downside, his injury problems continued to slow him down, especially in the playoffs as a knee issue kept him off the court. He underwent an arthroscopic procedure on his left knee in April.
The 30-year-old was at least healthy enough to play 75 games in 2018-19, but he averaged just 55.3 games per season over the previous four years.
It's a far cry from when he missed just four total games over four seasons between 2010 and 2014.
As good as he is on the court, it appears another health issue is slowing Griffin down and preventing him from reaching his potential. On a roster without much depth, an extended absence could be devastating for the Pistons.
Markieff Morris should see extra minutes if the All-Star is forced to miss time.
The Pistons will open the 2019-20 season on Wednesday against the Indiana Pacers.