Though David Moyes saw positives in his side's 1-0 defeat to Liverpool, the United manager left Anfield uncertain over the extent of injuries to two first team regulars.
While the champions were nearing full strength ahead of Sunday's trip across the north-west, a pair of knocks involving Phil Jones depleted their ranks in a costly couple of days.
The defender made way for Antonio Valencia after 37 minutes at Anfield, having landed awkwardly when contesting an aerial challenge, and the FA confirmed on Sunday night that Jones would miss England's upcoming World Cup qualifiers against Moldova and Ukraine.
"He had a bad twist on his ankle and it blew up right away," Moyes told reporters at his post-match press conference.
In another unfortunate twist, the manager confirmed that it was Jones who was responsible for Wayne Rooney’s absence from the squad which travelled to Liverpool.
“It was a complete accident [in training], Jones turned in and lifted his boot as Wayne came in and caught his forehead,” the United boss explained.
“It’s bad. He has a cut right down the middle of his forehead in an area which takes a while to heal; I think he’ll be out for around three weeks.”