Dean Moxey has become Derby's second signing of the week after completing his move from Exeter.
The 23-year-old has signed a three-year deal and joins the Championship club for an undisclosed fee, believed to be in the region of £300,000 plus add-ons.
Moxey agreed personal terms and passed a medical at Derby's Moor Farm training ground on Friday.
His arrival follows that of former Norwich winger Lee Croft, who signed on a free transfer on Thursday.