Wayne Rooney left the Allianz Arena on crutches on Tuesday night, after injuring his right ankle in the final moments of United's 2-1 loss to Bayern Munich.
The sight of Rooney limping off the pitch after landing awkwardly will worry fans worldwide, especially with the Champions League quarter-final second leg only a week away, not to mention Chelsea's lunchtime visit to Old Trafford on Saturday.
United confirmed on Wednesday that the Reds' medical staff are monitoring the injury and would await the results of a scan and further assessment before the extent of the problem is known.
Sir Alex Ferguson said on Tuesday night that it was too early in the aftermath of the Bayern match to assess the severity of the injury. "We’ll just have to wait and see," he said. "Hopefully it’s not too serious. He might be doubtful for Saturday against Chelsea but we don’t know for sure."
ManUtd.com will be first with any official news on Rooney's injury.