Robin van Persie has been ruled out for a month with a thigh injury, Manchester United manager David Moyes confirmed in a press conference.
Moyes said that the injury happened when the Dutchman took the corner from which Phil Jones scored in United's 1-0 win over Shakhtar Donetsk on Wednesday night.
"Robin van Persie is out as well for a month," Moyes told reporters. "He picked up a thigh strain in taking a corner kick which led to the goal.
"It's 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 scored 30 goals in all competitions in his debut season for United last term.
