Speaking in the embargoed part of his press conference to preview Thursday's home match with Southampton, the boss said there was understandably some fatigue on the back of the stirring Emirates FA Cup third-round triumph over Arsenal at the weekend.
Amorim admitted to MUTV there may be a time for fresh minds and fresh legs and Diogo Dalot is definitely ruled out through a one-match suspension for his red card at the Emirates Stadium.
Harry Maguire was withdrawn before the end and Lisandro Martinez was pushed up front, in the closing stages of extra-time on Sunday, but was fit enough to expertly convert his penalty in the shootout.