are poised to complete the signing of defender Efe Ambrose on a short-term contract on Monday.
The 30-year-old free agent arrived at the club last week, as revealed by Sportsmail
, and had his medical but the official signing of paperwork was held up over the weekend as Derby prepared to face Hull City on Saturday.
Ambrose last played a competitive game at the end of December before triggering a clause to be released from his contract with Hibernian in January.
He has kept himself fit and enjoyed a few days training with Derby ahead of finalising his contract.
Manager Frank Lampard had previously said that strengthening the defence was 'crucial' if they are to maintain their Championship promotion challenge.
Lampard said: 'We know we have an area at centre back where we are certainly lacking cover/competition. Trying to get people fit who may be haven't been training is a challenge.
'With Ashley Cole, it has been a challenge, he is nearly there. Now we are talking about Efe Ambrose, who hasn't been playing, so that will be a challenge but if it feels a challenge worth taking to improve the squad, I have no fears about doing it.
'I have found him very nice, very good, very friendly, so as a character I think he would be great for us anyway.
'I watched a lot of him, I know his strengths. He is a tall defender, very committed, wants to play on the ball, and quick.
'It is just about making sure about his level of fitness and that both sides are happy it is going to work.
'Efe hasn't played a competitive match since the end of December. It was good for us to have a look at him in this way. If a deal is done, we will let everybody know.'
A season-ending injury to Curtis Davies left Lampard without his captain, and further injuries at the back prompted the former England midfielder to say in January that first-choice duo Richard Keogh and Fikayo Tomori needed help.
'We know we needed a centre-back,' Lampard added. 'I felt we would get someone but that didn't happen. Efe is here outside of the window and if he can come in then great.'