Head coach Steve Kerr confirmed the 2015 NBA Finals MVP will not be available because of his left knee injury, per Anthony Slater of The Athletic.
Iguodala has been out since suffering a left lateral leg contusion in Golden State's 126-85 win in Game 3.
Slater noted the soreness Iguodala was experiencing worsened overnight following Game 3.
With Iguodala out of the lineup, Golden State has dropped the past two games in the series. The Rockets are one win away from ending the Warriors' streak of three straight appearances in the NBA Finals.
Prior to Game 5 on Thursday, Iguodala noted he was just doing everything in his power to make sure he's ready to play at 100 percent when he returns.
"Last game was the plan," he told ESPN's Chris Haynes. "Tonight was the plan. So, it's all about timing. Just trying to get it right. Make sure I can go."
The Warriors don't feel confident in Iguodala's ability to play without restrictions at this point. They will be tasked with slowing down the Rockets offense and trying to force a Game 7 back in Houston on Monday.
The good news for Golden State is defense hasn't been a problem the past two games. The Rockets have shot 38.1 percent combined in Game 4 and 5.
Getting their offense back on track is the bigger key for the Warriors, who would benefit from Iguodala's passing and playmaking.