Derby have completed the permanent signing of highly-rated defender Tom Naylor.
Naylor moved to Pride Park on loan from Blue Square Bet Premier club Mansfield in November and the 20-year-old has now signed a contract that will run until the summer of 2015.
Naylor has yet to make a first-team appearance for Derby, who have paid an undisclosed fee for the centre-half, but he has impressed manager Nigel Clough in training and with his performances in the Rams reserve side.
"Tom has settled in really well and we are pleased with the progress he has made at this stage," Clough told the club's official website. "We said when he arrived on loan that we feel he is a player who can, in time, develop and improve into becoming a Championship player and that remains the case.
"The intention was always to bring Tom to the club permanently and we are delighted he will be with us for the long term."
Naylor came through the youth system at Mansfield and made his debut for the Stags in April 2009. He has had loan spells at Belper Town and Alfreton Town and helped Mansfield to reach the FA Trophy final last season.