Rams boss Paul Jewell revealed a bid had been received at the weekend which is thought to have come from Derby's fierce local rivals Nottingham Forest. Norwich and Cardiff are also thought to be in the hunt for the Wales international.
Kevin Blackwell's Blades are well blessed up front with James Beattie, Rob Hulse and Billy Sharp having cost big money in the last few seasons. The Yorkshire side beat Norwich to the signature of Sharp last term, and have the trump card of Hulse reportedly being a target for Jewell.
Derby are also apparently reluctant to sell to Forest because of the nature of their rivalry with their near neighbours.