Manchester United have just one player sidelined for our Premier League clash at Tottenham Hotspur Stadium on Saturday (12.30pm UK).
Argentina defender Lisandro Martinez continues his road to recovery after suffering a serious knee injury against Palace in early February.
Speaking at his pre-match press conference, Amorim - named the Premier League Manager of the Month for October on Friday - said: "It’s one game every week and then a little bit of luck, because sometimes you have problems with players with knocks, it’s not something that is soft tissues.
"So you never know what is going to happen in the next training. If you play with intensity in training, something can happen, but I think the big reason... of course, we try to do everything well, the big reason is one game every week.
"You can give one extra day to the players that you know could struggle in the next training. I think that is the biggest reason."