After Aaronson got hurt Sunday, the U.S. Soccer Federation had said he would report to the national team on Monday in Houston. A source told ESPN's Kyle Bonagura an MRI showed a slight tear in Aaronson's MCL, which won't require surgery but will keep him out of action for 3-6 weeks.
"After reviewing the updated medical information and in consultation with Red Bull Salzburg, we have determined that Brenden Aaronson would not be available to play in the upcoming World Cup qualifying matches,'' the team said in a statement Monday.
"We were hopeful he would be able to recover in time; unfortunately, that will not be the case.''
Aaronson did not travel to the U.S. The American team said it was not sure whether he will be replaced on the roster, which has 26 players remaining.
The 21-year-old from Medford, New Jersey, had been the only U.S. player to appear in all of the first 11 qualifiers, starting seven. He scored against Canada and Honduras in September. Aaronson has three goals in 21 league matches this season.
Canada leads North and Central America and the Caribbean with 25 points. The U.S. and Mexico are next with 21 points, and the U.S. is ahead on goal difference. Panama is fourth with 17 points, followed by Costa Rica with 16 and El Salvador with nine.
The Associated Press contributed to this report.