The World Player of the Year missed last Saturday's 0-0 draw at home to Greece with what the FPF described as a left thigh injury.
Portugal are training near New York and face Mexico in a friendly in Boston on Friday.
Ronaldo struggled with minor injuries during the closing weeks of Real's season before playing 120 minutes in last month's Champions League final against Atletico Madrid and scoring the final goal in their 4-1 win with a penalty.
Portugal's opening World Cup match is against Germany in Salvador on June 16.
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