Deco has been ruled out of Portugal's Group G match against North Korea on Monday through injury.
The midfielder is struggling with a hip injury which has forced him to miss training for the last two days.
Portugal coach Carlos Queiroz confirmed Deco's absence for the clash with North Korea, but is hopeful the playmaker will be available for the final group game against Brazil.
Pains"He complained about left hip pains in training, it's something that has arisen before," said Queiroz.
"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)."
Queiroz is confident Portugal have enough strength in depth to cope without Deco.
"Deco is an important player but we have others too," added Queiroz.
"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 in the opening game against Ivory Coast and then substituting him before issuing an apology for his criticism.
Queiroz 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," insisted Queiroz.
Meanwhile, Portugal talisman Cristiano Ronaldo is hoping to break his World Cup duck against North Korea, but he admits winning the game is his main concern.
"I hope to score tomorrow," said Ronaldo. "To tell your the truth, I'm not concerned with scoring so many goals. My main concern is to win. If we win by 1-0, or 2-1, that's also satisfactory."
Queiroz is also hoping to see Ronaldo get off the mark as Portugal look to secure their first win of the tournament.
"Of course I want everyone, including Cristiano, to score. But the most important thing is a victory. It doesn't matter who puts the ball in the net," Queiroz said.