Goalkeeper Zack Steffen will miss the United States' exhibition match against Peru, with either Brad Guzan or Ethan Horvath starting in East Hartford, Connecticut, on Tuesday.
The U.S. Soccer Federation said on Saturday that Steffen has a tight right hamstring and has left the training camp.
He started the last four U.S. games, including Thursday's 4-2 loss to Colombia in Tampa, Florida.
Guzan, a 34-year-old veteran of two World Cup squads and 58 international appearances, is with the national team for the first time since the loss at Trinidad and Tobago last October that ended the Americans' streak of seven straight World Cup appearances.
He has not played for the U.S. since Sept. 5 last year, a 1-1 draw at Honduras in a World Cup qualifier.
Horvath, 23, has played twice for the U.S., exhibitions against Cuba in October 2016 and at Portugal last November.