The Al-Nassr forward sustained an injury during a match against Al-Fayha in the Saudi Pro League earlier this month and traveled to Spain for rehabilitation, missing the last two games of his club.
The 41-year-old is working towards being fit for the World Cup, which is anticipated to be the last major tournament of his career.
Martinez will instead rely on Ronaldo’s club teammate Joao Felix among the ten forwards included in the 27-player squad for the North America tour.
Manchester City players Ruben Dias and Bernardo Silva, along with Tottenham Hotspur midfielder Joao Palhinha, were omitted, while Goncalo Guedes received his first call-up since 2022.
Portugal will compete against Mexico on March 28, followed by a match with the United States on March 31.
They will also face Uzbekistan, Colombia, and a play-off winner in Group K.
The World Cup is scheduled to take place in the U.S., Canada, and Mexico from June 11 to July 19.
