Margetson will retain his playing status and be the third choice keeper. At the moment that's behind Neil Alexander and new signing Mark Howard.
The papers are continually linking Neil Alexander with a move away from Ninian Park. Coventry are strongly mentioned with the thinking being that if Alexander goes for a decent fee City will turn to Liverpool's Scott Carson on loan for the season.
Howard would be No.2 with Margetson third choice as cover.
Speaking to the Echo Margetson tells how it all happened
'It was a call from Dave Jones, who said he had a proposition for me,' said Margetson.
'He offered me a dual role as player/coach.
'My first thought was for George Wood, who had been goalkeeping coach at Cardiff for such a long time and helped me personally so much.
'But when the gaffer rang to offer me the job he had already made the decision to release George.
'It was a difficult situation, but I rang George and we spoke at length.
'It's a measure of the man that he told me to go for the job.
'After having that chat to George I knew things would be fine.
'I know I will be third choice goalkeeper next season, but I will train every day with the other lads and it's a big opportunity for me.
'I feel I have a lot to offer after 18 seasons playing professional football.
'I have worked with so many goalkeepers and goalkeeping coaches.
'I am starting work on my coaching badges immediately and I realise I have to get those done as quickly as possible.
'Now, though, I'm looking forward to the challenge.
'We had already made a family decision that we would not move away from South Wales, which restricted me in terms of how many clubs were within travelling distance.'