Portugal coach Paulo Bento said Cristiano Ronaldo, Raul Meireles and Pepe could feature in Tuesday's friendly with the Republic of Ireland.
The trio all returned to the training track from injury recently, in the race to be fit for Portugal's FIFA World Cup opener against Germany in Salvador on June 16.
Ronaldo (knee), Meireles (thigh) and Pepe (left leg) have all brought niggles with them to Brazil, but they took one big step in their respective recoveries by undergoing training on Monday.
A week out from their Group G curtain raiser, Bento said he will assess how they pull up when deciding whether they feature for the New Jersey friendly.
"Regarding the fitness of Cristiano Ronaldo, Raul Meireles and Pepe, the first two trained on Saturday and Sunday and Pepe trained today," Bento said on Monday.
"Their situation will depend on what their response is to this training. We will see what our decision will be for tomorrow's match against Ireland.
"Of course it's difficult to train without the full squad, it will all depend on how they feel before the match against Germany and of course it's always difficult to prepare for such a big match without all the squad there, able and fit."
Bento said he was not looking past their group fixtures with the Germans, USA and Ghana, despite the Portuguese side advancing into the knockout rounds at the past two World Cups.
"Our first objective is to go through the group stage, to the knockout phase," he said.
"Before thinking about the knockout phase we will have to focus on that first objective which will be to achieve and pass through the group stage.
"From then, we will try to compete against any opponent we will face and try to progress and go as far as possible."