The Chilean completed his move to Old Trafford from Arsenal on Monday in a swap deal with Henrikh Mkhitaryan and will get his first taste of competitive action at the first time of asking.
Sanchez, who will wear the famous No. 7 shirt, looks set to line up on the left-hand side of the three behind Marcus Rashford as United look to progress to the FA Cup fifth round.
Speaking of Sanchez's inclusion, United boss Jose Mourinho told 'BBC Match of the Day': "Alexis Sanchez had a couple of training sessions with us. He was not in his best condition but we think the best way for him to adapt and recover his normal fitness is to play. He loves to play and wants to play. For us it is not about Alexis it is about the match and the FA Cup. The FA Cup can have an incredible day tomorrow, but hopefully not tonight.
"I love the feeling of the Cup but I love the fact we have travelled far and brought Manchester United to a place we are not coming often."
26 January 2018