Breckin has been Moore's assistant manager at both Rotherham, where the pair took Rotherham up from Division 3 to Division 1 and at Oldham Athletic next season.
Another change on the coaching staff is the departure of long-serving coach John McMahon who has left to join Shrewsbury Town as assistant-manager.
McMahon, brother of former Liverpool player Steve, was caretaker manager in the 2003/04 season after Ray Mathias got sacked until Brian Little was appointed.