The Dutchman was substituted before the end of the first half after falling into a pit at Loftus. United claimed a comfortable 2-0 victory over league strugglers QPR and took their lead on top of the table to 15 points.
Van Persie has been the difference for United this season, scoring 19 goals, the leading goal-scorer in the league so far, but was replaced by Danny Welbeck after falling into a photographer's pit.
Despite his absence United went on win 2-0 thanks to goals from Rafael and Ryan Giggs. Wayne Rooney, who missed the clash against Reading due to a sinus problem, made a second-half appearance on Saturday.
United drew 1-1 at the Bernabeu in the first leg and manager Sir Alex Ferguson is hopeful Van Persie will be available for the return leg.
"I hope he'll be ready,' Ferguson said. "He collided with a camera in that dugout piece of ground. He's got a sore hip. I imagine it will be tender and sore for a few days."
Prior to the Champions League clash at Old Trafford United take on Norwich City.