The club have sacked the defender, who sustained a season-ending injury in a car crash the club described as an "alcohol-related incident"
Derby have terminated the contract of club captain Richard Keogh over his involvement in an incident that saw two other County players arrested.
Keogh, along with Derby players Mason Bennett and Tom Lawrence, were involved in a car crash that the club described as "an alcohol-related incident" on September 24.
Bennett and Lawrence were subsequently charged with drink-driving, while Keogh sustained a season-ending knee injury.
The defender has since had surgery that is expected to keep him out for 12-14 months following a lengthy rehabilitation process.