Dion Sanderson's red card at Bramall Lane did not just cost Derby a win. It stripped away one of the very few defensive options John Eustace can still call upon, and it landed at the worst possible moment for a club sitting 23rd in the Championship table, four points adrift of safety.

A back four held together with tape

Derby have started four consecutive league matches with largely the same defensive unit: Joe Ward, Sondre Langas, Dion Sanderson and Ryan Hedges. That quartet was not Eustace's first choice; it was what remained after a cascade of injuries removed virtually every preferred option before a ball had been kicked.

Langas lasted 12 minutes of the QPR fixture before limping off, with Ryan Nyambe stepping in. Derby conceded twice in what followed. Against Stoke and then Sheffield United, the back four that finished the QPR game started again, and produced, in fairness, something marginally more composed. Then Sanderson received his red card, and the picture darkened further.

Eustace now heads to The Den on Saturday without his most experienced centre-back available for selection. The options behind Sanderson are threadbare. Matt Clarke, last season's player of the season, has not featured at all this campaign. Derry Murkin, first choice at left-back, remains sidelined. Eiran Cashin, Sondre Langas, Charlie Taylor and Craig Forsyth are all out, each with a different expected return date. The signing of Jack Robinson on a short-term deal in the immediate aftermath of the QPR defeat spoke volumes about how thin the squad has become.

Zetterstrom kept Derby in it

The one piece of encouragement from the Sheffield United draw was the return of Jacob Widell Zetterstrom in goal. The Swedish goalkeeper, coming back into the side after a spell out, produced the saves that earned Derby a share of the points. Had he not, the Rams would have left South Yorkshire with nothing. A goalkeeper cannot carry a defence indefinitely, but Zetterstrom's presence at least gave the back four something to fall back on.

Attacking output has not been the central problem. Derby have created chances across these four games and could reasonably claim to have deserved more from some of them. The issue is that a disorganised, rotated, injury-hit defensive unit keeps leaking at the critical moment, turning potential points into dropped ones.

Between now and January

Most of Derby's injured defenders are expected to return around the Christmas period. If that timetable holds, Eustace will eventually be able to name something close to a settled, experienced back four for the first time this season. The problem is the table will not wait. Four points separate Derby from Watford in 21st; that gap can widen quickly across a run of fixtures that continues to come fast.

Eustace has been composed in public, but the mathematics are straightforward. Every game that passes without defensive improvement is a game that makes the climb harder. Millwall away this Saturday, without Sanderson, is as difficult a fixture as the schedule could have produced at this particular moment.

The injury crisis explains a great deal of what supporters have watched this season. It does not, however, change the points column. Derby need Eustace to find something within what he has, because the players currently missing are not coming back this week.

Frequently asked

Why is Dion Sanderson suspended for Derby?
Sanderson received a red card during Derby's 1-1 draw at Sheffield United, ruling him out of the next Championship fixture.
Which Derby defenders are currently injured?
Matt Clarke, Derry Murkin, Eiran Cashin, Sondre Langas, Charlie Taylor and Craig Forsyth are all sidelined, with most expected back around Christmas.
Where are Derby County in the Championship table?
Derby sit 23rd, four points behind Watford in 21st and outside the safety zone after four matches without a win following the international break.