Lingering doubts about the fitness of world player of the year Cristiano Ronaldo has left Portugal in disarray ahead of its World Cup Group E clash with the United States in Manaus.

Already reeling from a crushing 4-0 defeat to Germany in its opener, Portugal faces almost certain elimination if they lose to the US, which beat Ghana 2-1 in its first match.

But preparation for the game could not be going much worse.

Although the Portugal camp insists Ronaldo is fit, he has been seen sporting an ice pack on his knee at training sessions and leaving early as his teammates continued to train. He was also far from his scintillating best against the Germans.

Much media speculation has focussed on whether or not he will play against the US, or indeed if he does, whether or not he will be fully fit.

But fellow forward Helder Postiga was adamant too much is being read into an ice pack.

"I personally think that the Cristiano Ronaldo talk is a bit too much so I imagine how he must be feeling about that," Postiga said.

But Ronaldo is just one of Portugal's problems as they will be missing several other players. Center-back Pepe has been suspended for one match after his red card against Germany for head-butting Thomas Mueller.

Fabio Coentrao has been ruled out of the tournament with a torn thigh muscle while forward Hugo Almeida has a pulled hamstring.