AC Milan's USA defender Oguchi Onyewu will be out for up to four months after suffering a serious knee injury during their 2-2 draw with Costa Rica.
Onyewu landed badly after jumping for a header and immediately called for assistance. He was taken off the field on a stretcher and was later found to have torn a patellar tendon in his left knee.
"We've had two days of tough news," said US coach Bob Bradley.
"'Guch' is such an important part of our team. He's young, he's healthy. Our doctors are good but nonetheless, it's another setback for us," he said.