Sheffield United skipper Michael Doyle and Febian Brandy were both withdrawn due to fatigue and not injury during the loss to Preston.
Midfielder Doyle was replaced in the closing stages by Stephen McGinn, while Darryl Westlake was an 80th-minute substitute for winger Brandy, who had returned to the starting line-up following a three-match ban.
"Febian had ran his race and we didn't want him to damage anything once he was clearly feeling fatigue," Blades boss David Weir told the club's official website.
"Michael had simply run himself into the ground too, as skipper, he typifies the desire the lads have to succeed.
"This football club is packed with great people, we want to bring success to Sheffield United, these are testing times but again I just want everyone to remain behind us."
The Blades are third from bottom in League One after slumping to a fifth straight league defeat on Saturday, but Weir, in his first job as manager, added: "It would be easy to curl up in a ball in the corner and hide, but me, the staff and the players will all respond positively and we will come out fighting again.
"We start again on Monday morning, that is the nature of the job, we will go again during the week and look to get a positive result at Wolves on Saturday."