The Warriors won Sunday's Game 1, 121-109.
Nurkic arrived at Oracle Arena on Sunday and made his way directly to the Blazers' locker room.
Coach Terry Stotts said Nurkic wasn't ready to return, and had to go with a "center by committee" approach against the top-seeded Warriors.
"Hopefully he'll be back at some point in the series," said Stotts.
Nurkic has missed seven games with a nondisplaced right leg fracture.
There had been speculation that the 7-footer known as the Bosnian Beast could return for the playoffs. He was seen shooting during warm-ups for the last two regular-season games, and he' was walking with no apparent limp.
The center, traded to Portland on Feb. 12 from the Denver Nuggets, was averaging 15.2 points, 10.4 rebounds and 1.9 blocks in 20 games with the Blazers.
Since his arrival in Portland, Nurkic has been embraced by Portland fans. He's credited with boosting the team as it made a final push for the playoffs: The Blazers finished in the eighth and final playoff spot in the Western Conference, clinching a spot ahead of the Nuggets with two games left in the regular season.
The Associated Press contributed to this report.