USA defender Oguchi Onyewu had surgery this week to repair a ruptured patellar tendon in his left knee, that he injured in the recent World Cup qualifying game against Costa Rica.
After the game the U.S. Soccer Federation estimated that his recovery at three to four months, but the federation issued a new estimate of six months on Thursday after his operation.
Six months puts Onyewu recovery around April 2010, giving him little time to regain match fitness before the World Cup, which starts June 11 in South Africa.
Onyewu is not the only injury worry for U.S. boss Bob Bradley. U.S. and Watford defender Jay DeMerit also had surgery last week. In his case it was cornea replacement operation. DeMerit is hoping to be back playing for Watfors early in the New Year.
Another U.S. player doubtful for the World Cup is forward Charlie Davies who is is likely to miss the World Cup after sustaining serious injuries, including several broken bones, in a car crash recently.