Tony Mowbray says certain players were rested against Doncaster Rovers for a fear of burnout.
The boss made six alterations to the side that started at Birmingham City a week earlier, with game time handed to the likes of Aynsley Pears, John Buckley and Tyrhys Dolan against Doncaster Rovers on Saturday afternoon.
There were plenty of first team regulars on the bench, with Adam Armstrong, Harvey Elliott and Joe Rothwell all emerging as substitutes in the second half.
Armstrong had featured in 24 of Rovers' 25 games so far in 2020-21 prior to the cup clash, whilst Elliott, at 17, had also played more games than he has been used to in his career.
“It was important to refresh the likes of Armstrong and Elliott, Rothwell, people like that," Mowbray began when detailing the reasons behind the changes to iFollow Rovers.
“They’ve played a lot of games and it was a chance to switch off a little bit for them.
“I don’t think I gave anyone a chance who hadn’t been in and around the squads this season, there were no debutants.
“It was a case of moving a few players around, this is our squad.
“We couldn’t get ourselves in front, which has happened fairly often in recent weeks, and we couldn’t recover as we have done quite a few times in the past."