Derby County manager Nigel Clough says he is reluctant to sign players in January even though he knows he is not blessed with defensive options.
The in-form Rams have won three out of three in the Championship and four on the spin in all competitions.
And Clough told BBC Radio Derby having a settled rearguard during that run, coupled with financial considerations, makes it tricky to strengthen.
"It's difficult to get players when you can't promise a start," he said.
"Players see three clean sheets out of four and a settled back four and if you ask somebody, they say 'am I going to play?' and we can't guarantee that."
Experienced centre-backs Jason Shackell and Shaun Barker have formed an impressive defensive pairing in recent weeks, with John Brayford and Gareth Roberts occupying the full-back positions.
And although Jake Buxton is another option at centre-back, Clough does not have strength in depth - particularly in the full-back area.
Brayford's versatility means he provides options across the backline and new arrival Tom Naylor can also operate in the centre and out wide, but further injuries could seriously hamper any possible promotion challenge.
But for the time being, the Clough is happy to stick with what he has.
"We don't want to tie up funds unnecessarily," the former Burton boss added. "If we lose a full-back we will react to it and try to get somebody in as cover."