Lee Bullock will undergo a hernia operation on Monday that will rule him out of the bulk of City's remaining games.
The midfielder, signed from Hartlepool in January, has been trying to play through the pain in the last month as his groin injury grew steadily worse.
Stuart McCall had hoped to delay surgery until the summer but felt Bullock could not wait that long.
He said: "Sometimes you can get through games and hold out but Bully wasn't doing himself or the team any justice.
"He was struggling to get round the pitch at Stockport and that's not like him.
"He was trying to play through to help the team out but it's sensible that he has the op as soon as possible. We want him back and feeling right and hopefully he can return for the last game or two.
"For his own mental state, it would be nice if he could get in at least another game before the end of this season."
Bullock's absence puts the onus on Eddie Johnson and Paul Evans in centre midfield and both delivered in the win at Chester. McCall is expecting more of the same against Mansfield on Saturday.
"I think that was the best Evo has played for us this season. And I don't know if Eddie felt he had to prove himself because it was against his home-town team but he also did a very good job.
"They got about the pitch, getting tackles in and showing a great desire. Now I want to see that all the time."
McCall was pleased with his side's response after losing the previous two.
"I told the players before the game that I could have made five or six changes after Stockport.
"Some had played okay but we need to be better than that because okay isn't good enough.
"You shouldn't get pats on the back for working hard - that should be a gimme in football. You can't always play well but you should expect people to go out there and give everything.
"We knew it would be a battle but we matched them and had that quality to win the game. Now we're up against another side fighting for their lives and I want to see us on the front foot again."
Omar Daley returns to the squad after a back strain forced him to miss midweek. TJ Moncur iced his sore hamstring after the Chester game but should be fine.
Mansfield, like the majority of the division, are far happier on their travels.
But McCall wants to see a home performance along the lines of the Shrewsbury, Notts County and Rotherham games and not the recent hiccups.
He added: "Mansfield seem to have the freedom to cut loose when they go away but then there doesn't seem to be any advantage from playing at home in this league.
"Since the turn of the year, we've scored four at home against Shrewsbury and three in the Notts County and Rotherham games and I want to see a return to that form. We've had a few bad ones of late in front of our own supporters and it's important that we play a lot better.
"Mansfield's away record is very good but it's always about what we do.
"We got a good result at Chester and I expect us to be able to build on that."