The Portuguese football federation says on its website that the Real Madrid star and injured Portugal teammates Pepe and Raul Meireles are all “unfit” and would miss the warm-up against Mexico at Gillette Stadium in Foxboro, Mass.
Ronaldo is recovering from tendinitis and a muscle injury, both in his left leg.
Portugal will play Ireland in an exhibition next Tuesday at New Jersey’s MetLife Stadium before heading to the tournament in Brazil.
At the World Cup, Portugal also plays the United States and Ghana in Group G.