The 15:00 BST kick-off at Old Trafford is our last fixture before the latest international break and a chance to pick up a third successive home victory, on the back of the wins over Burnley and Chelsea.
Casemiro is back after the Brazil international served his one-game ban, for the red card against Chelsea, during the defeat at Brentford.
Amad missed the trip south last weekend, following a family bereavement, but is available again after training at Carrington this week.
"They are really important," Amorim told MUTV's Mark Sullivan in his exclusive pre-match interview, when asked about the pair.