"It is not the ending I would have liked, but I think it is the right thing to do," Bolton said.
"I've spent nearly 11 months coming back from my achilles injury and I've got so close. I was confident I'd be able to play in the next few weeks, so I was pretty shattered from that point of view.
"It is tough but you've got to force yourself to look at the bigger picture and I've had a wonderful career here at the Swans."