Branagan said: “A couple of weeks ago I returned to training and started to step up my work. But then I went to make a routine save again and the pain hit me, hard. It felt like a bullet had shot straight through my shoulder.
"I went to see the specialist who had done the operation on Tuesday and after talking to him for a while, he told me the injury was never going to get any better and that I had to give up playing.
"Basically, if you take the shoulder as a ball and socket joint, I have nothing to ease the movement between the two. Consequently, the pain starts when the shoulder is activated in certain ways.
"I have never been at a club where a player has had to retire from injury before so it is unknown territory for me. I have been in touch with the PFA for advice and I'm sure that will be ongoing until everything is sorted out."