Derby are delaying Shaun Barker's knee operation until the club are safe from relegation.
Barker has played for much of the season with a knee problem and he is likely to be out for around 12 weeks following surgery.
But his importance to the team means the 28-year-old will continue to play through the discomfort while the Rams try to secure their Championship survival.
"We need him too much, and he will be out there until we don't need him," said Rams boss Nigel Clough.
"The specialist has said he cannot make the problem any worse so all we are doing is biting into pre-season time a little bit.
"Ideally, we would have had him in by now and had the problem sorted out but we need a few more points before we can do that."
Double worryMeanwhile, Clough is sweating over the fitness of Paul Green and Gareth Roberts.
It is feared the duo could miss the remainder of the season after suffering knee injuries against Cardiff.
The pair have been sent for scans on the injuries and the club are waiting to find out the full extent of the injuries.