Nigel Clough admits his decision to leave Crystal Palace loanee Paddy McCarthy on the bench for Saturday's draw with Walsall was because of the impressive form of Chris Basham and Jay McEveley at the heart of the Blades back four.
McCarthy, whose loan expires after next Sunday's date with Scunthorpe United, has been a regular since joining on a temporary basis in October, but the Gaffer has been happy with the partnership that has developed between Basham and McEveley in cup matches, despite both players beginning their United careers in different positions to where they find themselves now.
The Gaffer, who admitted losing Ryan Flynn to a hamstring problem at half-time against the Saddlers was a blow, also revealed planning has already commenced ahead of the January transfer window.
He commented: "It wasn't ideal leaving Paddy (McCarthy) out, it was harsh on him, but that back four has kept clean sheets against Plymouth and Southampton in the cup and looking ahead to January our centre-half partnership will probably be Basham and McEveley and they complement each other very well.
"Harrison (McGahey) did okay at right-back but when you get a centre-half playing there he can get tucked too far in and that happened for their goal.
"Thankfully Craig Alcock isn't too far away from a return as we have lost three right-backs in recent weeks.
"We are active now for when the Janaury transfer window opens, but what we have to do is improve the squad with the players we bring in because we already have a lot of good players."
Looking ahead, the Blades boss said he hopes to partner Chris O'Grady with Marc McNulty in attack in the near future, he added:
"Marc would have started if he had been fully fit, without revealing too much we want to see him play in a front two with Chris, so with two games coming up over three days that is a possibility sooner rather than later."