General manager Bob Myers noted Monday he could miss even more time:
This will keep the guard out for at least 55 games of the 82-game season.
The Warriors will likely remain conservative with the 29-year-old, who signed a five-year deal in the offseason worth $190 million.
Thompson said in August he doesn't expect to be back before the All-Star break.
"I've heard varying opinions about, especially medically, I don't want to rush it 'cause I want to play until I'm 38, 39, 40 years old," he told Cari Champion of ESPN. "That's my plan, especially because the way I can shoot the ball. I would love to see the floor this season. I don't know when that is."
As he recently noted to Marcus Thompson II of The Athletic, basketball players like Zach LaVine and Danilo Gallinari missed about a full year with the same injury, while Thompson was still a month away from even jogging.
Considering he didn't undergo surgery until July, this could keep him out for all of 2019-20.
It's clear Golden State will be without the five-time All-Star for at least most of the regular season, putting more pressure on Stephen Curry and the newly acquired D'Angelo Russell to help replace his production offensively.