Former England right-back Danny Mills has been forced to retire from the game due to a long-standing knee problem.
The 32-year-old, who has enjoyed spells with Norwich City, Charlton Athletic, Leeds United, Middlesbrough and the Citizens, has not featured in senior football since January 2008.
He told BBC Radio Five Live: "Unfortunately I have now got to the situation where I can no longer continue to play.
"So, really as from today, I'll be retiring from the professional game and looking to do other things.
"It has been difficult. I was fortunate it wasn't my decision in the end.
"I've been around the world - America, Germany, Sweden, London - I've been everywhere trying to get it sorted.
"I've been out for 18 months and I'm likely to have another operation in three or four months' time. Basically the knee just can't cope with it any more."