US midfielder Jose Torres underwent surgery on Wednesday to repair a broken bone on the outside of his left foot and will be sidelined for at least two months, US Soccer announced.
Torres' Mexican club, Pachuca, set the return timetable for the 23-year-old Texan after the operation on his fifth left metatarsal.
New American coach Jurgen Klinsmann, still searching for his first victory after three matches in the job, has started Torres in all three US matches since taking over the squad on July 29.
The loss of Torres comes a day after US midfielder Stuart Holden returned to the lineup for Bolton in a 2-0 victory against Aston Villa. Holden missed six months with a knee injury after a tackle by Manchester United's Jonny Evans.
Klinsmann will guide the Americans in two more home friendly matches against 2010 World Cup sides next month, facing Honduras on October 8 at Miami and Ecuador on October 11 in Harrison, New Jersey, as he looks to evaluate talent ahead of World Cup qualifying matches in 2012.
"We want to expose the team to as many styles as possible, and we know the quality of Ecuador," Klinsmann said.
The Americans are 2-4-4 against Ecuador, but have won their two most recent meetings, the last a 3-1 triumph in Tampa in 2007. The US squad is 11-3-3 all-time against Honduras.
Under Klinsmann, the US team drew 1-1 with Mexico last month at Philadelphia, lost 1-0 to Costa Rica at Los Angeles earlier this month and fell 1-0 to Belgium at Brussels on September 6.