Wayne Rooney faces 3 weeks out with knee injury

Manchester United’s Wayne Rooney, center, celebrates with Ashley Young, left, and Robin van Persie after scoreing his sides first goal during the Manchester City against Manchester United English Premier League soccer match at the Etihad Stadium, Manchester, England, Sunday Dec. 9, 2012.(AP Photo/Jon Super)

MANCHESTER, England– Manchester United striker Wayne Rooney faces spending up to three weeks out with a knee injury.

Manager Alex Ferguson says the injury was sustained while the player tried to hit a volley toward the end of training on Tuesday.

Ferguson says Rooney “strained a ligament behind the knee. It’s unfortunate, and he could be out for two to three weeks.”

The England international missed United’s 4-3 win over Newcastle on Wednesday.

Ferguson didn’t specify which knee was injured.