The England striker has sustained a toe injury and faces a race against time to get fit in time for the Champions League quarter-final second leg tie in Germany
Rooney will miss United's trip to Newcastle on Saturday after manager David Moyes revealed the striker was struggling with the toe injury he sustained during last Tuesday's 1-1 draw against Bayern at Old Trafford.
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"Wayne's got a badly bruised toe," Moyes told MUTV. "He picked it up in the game the other night. Whether we were going to play him or rest him, it doesn't matter.
"He's got a terrible toe and not only will it be a problem for this game, it could be a problem for the Munich game as well on Wednesday.
"So we need to monitor it. We'll get him treatment all over the weekend and see if we can speed it up."
England manager Roy Hodgson will also be monitoring developments closely, as an injury to his star man would seriously hamper his preparations for the World Cup.