The 29-year-old made 301 professional appearances throughout his career which included time at Southampton, Wycombe Wanderers, Walsall, Barnsley, and Millwall. McCarthy hung up his boots to join the support team of head coach Shannon Ruth as he enters the world of coaching for the first time.
Academy manager Ian Buckman spoke on the ex-defender and revealed that he was the perfect candidate after a final round of interviews which also included former Brighton midfielder Steve Sidwell.
“After a thorough process, we’re delighted to welcome Jason to the club. He is a great fit for the profile of coach we wanted to appoint and is an exciting addition to the staff.
“He has a huge amount of recent experience in the professional game as a player and a big desire to make the step into coaching.
“We believe that he can be a really positive influence on the under-21s and look forward to the future with him.”