United and England winger turned full-back Ashley Young faces a "long time out" after Louis van Gaal confirmed he will need surgery on a severe groin injury.
The 30-year old sustained the injury in United's 1-0 victory at Anfield last weekend and what initially looked a minor problem has now proved to be a lot worse than first feared.
Young has enjoyed something of a renaissance under LVG, enjoying his best season in a United shirt last term as one of our most improved players and he has continued that form this season despite often filling in at full-back.
Converted from a conventional winger, the versatile Young has made the vast majority of his 23 appearances this season at right-back, but he has also lined up at left-back and as an occasional wing-back in a 3-5-2 system.
He has stood out as one of the side's most creative outlets, and in a side often lacking in ideas and invention and- like Luke Shaw- his pace, penetration and 'beat your man' mentality will be a big loss to the Reds.
His absence adds to a list of injures in wide positions, prompting Van Gaal to admit that he may consider bringing in new signings with Matteo Darmian now our only fit senior available full-back.
Left-back Luke Shaw looks set to miss most of the remainder of the season with his broken leg, Marcos Rojo has had shoulder surgery, Phil Jones has an ankle injury and Antonio Valencia is a long-term absentee with a foot injury.
18-year-old Cameron Borthwick-Jackson put in an impressive cameo at Anfield when he replaced Young and looks set to come in on the left tomorrow, whilst 22-year-old Guillermo Varela could also be drafted in.
"He has to have an operation so he will be out for a long time, it is not just a month or so but longer and we already have big problems in the full-back positions.
"It is unbelievable, we are not lucky with that
"I have used youngsters a lot of time and Varela and Borthwick-Jackson are doing great, but the level at Manchester United is high so it is difficult for youngsters to do that for every week so we are looking for re-inforcements as our solution."
In a side lacking in pace, it's a cruel blow that United's two main speed merchants Shaw and Young have both suffered long term injuries simultaneously, leaving both of Van Gaal's preferred left-sided options sidelined.