The Daily Star says Rooney has been suffering with a groin problem that has ruled him out since New Year’s Day.
United sent him on a warm weather training break to Egypt in the hope he could recover in time to face Jose Mourinho’s men.
Rooney travelled to north Africa with his family and United’s head of human performance, Richard Hawkins.
But it is understood he has struggled to overcome the nagging problem and is now rated no better than 50-50 for the showdown at Stamford Bridge.
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