Matteo Darmian, who started against Palace, was also missing from Monday's training, along with Marcos Rojo.
Never in their history have they failed to hit the net in three consecutive European home ties.
Palace have only scored one goal in their last four matches in all competitions but manager Roy Hodgson was pleased with his side's solid display at the back.
"We're talking about Luke Shaw, Martial, Lingard, Rashford - young, big potential, but at the end of the day it results in the word I can not say [cojones], but you use it a lot here. character, personality, they lack a little".
Macari is unsure whether some of the players will be able to step up and give a better account of themselves at Manchester United, but insisted Mourinho needs to do his job in order to get the best out of them.More news: Snowstorm batters parts of Midwest, 100s of flights canceled
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"But we need to take on board what is said [by the manager] and we have to fight for him and the team, the fans and for the club".
"The last couple of days everyone has been a disappointed it was a massive game [against Palace] after global break and we needed to get the win. If we can have Victor available for that period, that will be good". "Everyone in the changing room is a fighter and we want the best for the team and the club".
Shaw, Marcus Rashford, Anthony Martial and Jesse Lingard were named by the United boss in a interview with U.S. Spanish-language outlet Univision last week but the England full-back says he has not taken it to heart.
"There's a lethargy, in terms of the fans going into the ground, watching the game, players on the pitch".
Matteo Darmian said in the summer that he wanted to leave Manchester United, with a return to Italian football his most likely destination.
"But, look, what he said the other day, I think that was more a generation thing and I don't think it was really aimed much at us as individuals".
"We played a game like it was one more game and I don't think it was one more game".