The Blades boss would like to sign Morris but conceded that his wages could be too much for the Bramall Lane club but will turn his attentions to Aston Villa full back Alan Wright.
Lee Morris
"I have had several chats with his [Morris'] agent," Warnock told the club's official website. "But the wages he is on at Derby are way out of our league - and he has already turned down their latest offer anyway.
"I like Lee as a person and as a player and, like me, he is an out and out Blade. It's a shame but it really doesn't look as if we will be able to bring him in.
"Alan [Wright] is one of several I have spoken to although I'm delighted Kozzy [Robert Kozluk] has re-signed, so we still have some experience in that area."