Manchester United manager David Moyes says striker Robin van Persie will be out for a month with a thigh injury.
Van Persie, who has 10 goals for the club this season, was hurt in the Champions League win against Shakhtar Donetsk on Tuesday.
The Dutch striker could miss eight fixtures, including a League Cup quarterfinal against Stoke on Wednesday and a Premier League match against Tottenham on Jan. 1.
"That is a big blow to us," Moyes said.
"It is unfortunate because I think if you look at our record with Wayne Rooney and Robin in the team it is
actually very good, and we have not had them for quite a period recently."
Van Persie current season has been disrupted by toe and groin problems.
He returned to action in the 1-0 defeat to Newcastle last weekend after a month-long absence.
"Marouane Fellaini has a bit of a back injury.
"Michael Carrick is also missing."
News of van Persie's injury comes as United bid to bounce back from successive home defeats in the league, which have left them 13 points behind leaders Arsenal.
Moyes' side visit Aston Villa on Sunday.
Meanwhile, striker Wayne Rooney could make the 500th club appearance of his career against Aston Villa.
Rooney has scored 207 goals for Manchester United in all competitions and, according to Moyes, the striker could become a club legend.
"There are big things ahead for Wayne.
"He can break Sir Bobby Charlton's goals record [249 goals].
"There are some fantastic legends at this club... Wayne can be one."