Rob Hulse is in talks with Derby after Sheffield United accepted an improved offer from their Championship rivals.
The Blades have accepted an improved bid, reported to be £1.6million rising to £2million with add-ons, and the 28-year-old is at Pride Park ahead of a medical and talks over personal terms with Derby chairman of football Adam Pearson.
United manager Kevin Blackwell said: "We have agreed a figure with Derby and Rob has travelled to speak to them."
The £2.2million signing has a year left to run on his Bramall Lane contract but his progress was restricted last season after his recovery from a broken leg sustained at Chelsea in March last year.