21-year-old Mellor joined the Railwaymen back in 2008 from local neighbours Nantwich Town in a £20k deal.
Crewe-born Mellor then had loan spells back at his first club Nantwich Town, Newcastle Town, Stafford Roangers, Leek Town and last summer was sent on loan to Icelandic team IBV.
Mellor made his Crewe debut in the 2-1 away win at Morecambe back in November 2010 but it was not until the back end of March last season before he established himself in the first team and played a big part in the clubs run in to the play-offs and the final where he played in the final.
The Alex are believed to have offered Mellor a one year deal and after the first offer was rejected it seems that an improved offer has been tabled, but it seems that the lure of a three-year deal at Derby County could see the defender move to pastures new.
If Mellor agrees a move to Pride Park the club will be entitled to compensation in which Nantwich Town would take a percent.