Signing a quality defender is a high priority for Derby's Murdo Mackay after Wayne Thomas turned down a move to Pride Park in favour of Burnley.
The Rams director of football said: "We are looking for centre-back cover as Tom Huddlestone, who played there most of the season, won't be around.
"There's obviously Mo Konjic, Michael Johnson and Pablo Mills but we'd probably need a bit more cover there.
"We have to improve quality of the squad," he told the Evening Telegraph.