Derby County have now opened talks to sign an "unbelievable" defender, who is set to be available on a free transfer at the end of the month, according to a report.

Derby set to strengthen in defence

Derby survived the drop by the barest of margins last season, and they have their defence to thank, keeping clean sheets in four out of their last eight games to ensure Championship football will be played at Pride Park once again next season.

In the end, John Eustace wasn't left to rue the decision to leave Blackburn Rovers for the Rams, but a club of their stature will have far loftier ambitions than merely surviving in the second tier, and the manager is looking to put his own stamp on his squad.

Despite the stellar defensive efforts at the back end of last season, one position in which Eustace appears to be particularly keen to strengthen is centre-back, with the likes of Blackburn Rovers' Danny Batth and Birmingham City's Dion Sanderson of interest.

According to a report from Derbyshire Live, a League One centre-back has also been identified as a target, namely Lincoln City's Paudie O'Connor, with Derby recently opening talks over a deal for the defender.

O'Connor's contract is set to expire at the end of the month, meaning he is able to leave the Imps on a free transfer, and there are a number of clubs interested in his signature, with Huddersfield Town and Barnsley also being linked.

Wycombe Wanderers are currently believed to be in pole position for the Lincoln centre-back, but a move to Pride Park could be more appealing, given that Championship football will be on offer next season.

Derby need new centre-back after Phillips departure

The Rams' defence was not the main problem last season, considering they shipped fewer goals than Coventry City, who reached the play-off semi-final, but it is clear they will need to bring in a new centre-back this summer, as Nat Phillips has returned to Liverpool.

Phillips was a regular starter whenever fit, making 32 appearances in the Championship last term, and he even scored a vital goal away at Hull City in the penultimate match of the season, which proved to be crucial in Eustace's side avoiding the drop.

As such, it could be a difficult task to replace the 28-year-old, but there are some signs that O'Connor could be up to the task, having previously been lauded as "unbelievable" by teammate Jack Moylan.

The Lincoln captain was a key player for the Imps last season, making 45 appearances in all competitions, during which time he also proved himself to be a real attacking threat, picking up three goals and five assists in League One.

As such, the Irishman could now be ready to test himself at Championship level, and he would be a low-risk addition to the Derby squad on a free transfer.