Manchester United manager Ole Gunnar Solskjaer said midfielder Bruno Fernandes needed a break after the Portugal international was left out of the starting lineup for Sunday's 3-1 FA Cup quarterfinal defeat by Leicester City.
Fernandes, who been a stand-out performer for United with 23 goals and 13 assists in 45 games in all competitions, replaced Donny van de Beek in the 64th minute.
Explaining the decision to leave Fernandes out of the starting 11, Solskjaer said the 26-year-old had played a lot of football this season.
"He's also a human being, he's played a game every three or four days really," he added.
"I know Bruno wants to play but sometimes you make decisions for the benefit of both the team and him.
"Of course, we're disappointed we're out but probably it's just the sum of all the factors and all the games we've played lately, all the injuries.
"I don't want to make excuses but I try to find an explanation and an explanation is we had a few players coming back who have not really trained a lot. They've not played for a while and there are others who have played a lot but lacked a little zip and energy that we normally see.
"We conceded easy goals we don't normally concede and it's difficult against a good team like Leicester."
Solskjaer's counterpart, Leicester City manager Brendan Rodgers, said his team are aiming to create history by winning the FA Cup for the first time after Sunday's win moved them one step closer to the final.
Leicester have lost the FA Cup final four times, the last occasion coming in the 1968-69 season when they were beaten 1-0 by Manchester City, and Rodgers said it was time to end that run.
"We are in the semifinal and we have a chance to get to the final and create history," Rodgers said.
"For the club to get to the final and win the trophy would be really special. It's a trophy in their history they haven't won.
"It's a tough game in the semifinal but the club has never won the FA Cup so to be able to do something like that will be special."