The AC Milan defender fell on his left knee coming down for ball driven to the far side of the penalty area by Jose Francisco Torres on a corner kick in the 83rd minute of the game. Onyewu immediately screamed in pain and left the field on a stretcher. Since the USA had already made their three subs, they played the rest of the game with 10 players, tying the score in the fifth minute of stoppage time on Jonathan Bornstein's header.
"We've had two days of tough news," U.S. coach Bob Bradley said. "Gooch has been a such an important part of our team."
Bradley is confident Onyewu, 27, will recover in time for the World Cup.
"He's young, he's healthy, our doctors are good," Bradley said. "He's someone who we're sure is going to get back and be ready to go."