"Giles has not spoken to me to tell me what he is doing, but that's what you are up against," Dearden told the Nottingham Evening Post on Tuesday.
"It is disappointing, especially after how we have looked after him since he got the injury.
"But his agent has been touting him around because his contract is up, so this was a possibility, whether we looked after him or not.
"Ever since I came to the club, I knew Cokey wanted to move back down nearer to the London area.
"His wife and their young baby live down in London, so it will be a lot easier for him to travel there.
"It has been a difficult situation, but it goes without saying we will be looking to bring someone in to replace him."