"He complained about left hip pains in training, it's something that has arisen before," Queiroz told reporters after his team's light run-out at Green Point stadium.
"The medical teams examined him and they did an MRI scan. There was no improvement today, he didn't train, so they recommended he shouldn't play.
"I do believe though he should be ready for the final game against Brazil (on June 25)."
Deco played 62 minutes in Portugal's 0-0 draw against the Ivory Coast on Tuesday, before being substituted by Tiago, who is likely to start in his place against North Korea.
"Deco is an important player but we have others too," said the coach, who said he was yet to decide on his replacement.
"If you look at our qualifying games he played in some and not others and we have won with him and without him. We have a squad that can offer solutions to problems like this."
Deco criticised Queiroz for asking him to play out wide and then substituting him against Ivory Coast, later issuing an apology. The manager, however, was quick to dismiss suggestions that had any influence on his absence.
"There is absolutely no room for any conjecture or speculation, he simply felt the pain while training," Queiroz said.
The only real mystery surrounding the issue was the exact nature of the injury. Queiroz described it as a problem with his left hip, a FIFA translator switched that to his right hip, while the player's spokesman said it was his upper right thigh.
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