Chesterfield have extended Jonathan Grounds' loan spell from Middlesbrough after the defender helped the Spireites to three wins and a draw.
The 23-year-old defender's initial month-long stay at the League One club was set to end on Saturday but he will now remain with the Spireites until November 26.
Since making his debut at Exeter in August, Grounds has made six appearances which have included three wins and a draw.
Grounds was a member of the Middlesbrough academy before signing a professional contract with the Teessiders four years ago.
He has since made 37 first-team appearances for Boro and has had further loan spells with Norwich and Hibernian.