Rooney was still wearing the protective boot around his right foot that was in place when he left the Allianz Arena last night with an injury deemed serious enough to warrant normal security procedures being relaxed, both in Germany and the UK, as Manchester United returned from their 2-1 Champions League defeat to Bayern Munich.
The 24-year-old did not go through passport control in Munich and had a club-sponsored car to take him away from the airport immediately after he had disembarked the plane, having had to wait for the rest of the passengers to depart.
It is believed Rooney will have a scan, either later today or in the morning, that is likely to confirm a sprained ankle.
The extent of the injury will determine how long Rooney will be on the sidelines for, although early speculation suggests United will be without the 34-goal forward for at least a couple of weeks.
That would rule Rooney out of Saturday's crucial Premier League encounter with Chelsea, plus the second leg of the Bayern clash, when United will look to overturn a 2-1 deficit, and the trip to Blackburn on April 11.
It is likely to be Friday however before Sir Alex Ferguson reveals any further information about England's most famous footballer, who amusingly, was missed by the air steward deployed to return the crutches that had been placed at the back of the United plane during the two-hour flight.