The 26-year-old, who picked up the injury in Saturday's 2-0 Premier League defeat at Stoke City, will be further assessed by Spain's medical staff, the club said in a statement.
Torres had only recently returned to form after a poor spell in a struggling Liverpool side, scoring three times in as many games, including both goals in a 2-0 win over Chelsea this month.
World and European champions Spain play Portugal in Lisbon.
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