But striker Clint Dempsey and Matt Besler would be ready for the critical Group G match against Cristiano Ronaldo, US officials indicated in a Twitter statement.
Altidore "out" of the USA v Portugal game while Besler and Dempsey "are fit and available," the injury update said.
Altidore left the Americans' 2-1 victory over Ghana on Monday in the 21st minute with a left hamstring strain. Besler went out in the 41st minute with a right hamstring issue.
A team spokesman said they hoped Altidore would be fit for later matches, the next vital one being the group stage finale against Germany next Thursday.
"Obviously Jozy is a big part of our team," Dempsey said. "He played a big part in us getting here in qualifying. We'll have to adjust and everybody will have to step up. that's why we have substitutes."
Dempsey suffered a broken nose in the Ghana triumph and could use a mask to protect his nose from further damage in future matches.
Portugal need a victory over the Americans to get their World Cup back on track after opening with a 4-0 loss to Germany.
Victories by the Americans and Germany over Ghana would advance the US squad to the final 16, the same stage they reached in 2010 before being eliminated in South Africa by Ghana.