Bellamy attracted plenty of interest from Premier League clubs, but admits it would have needed a "miracle" to make the move from Eastlands to Old Trafford.
"Garry Cook (City's chief executive) said to me it was the most phone calls he'd had on a player for a while," Bellamy said.
"He said 'You should take that as a big compliment' and I said 'Yeah, they all seem to want me apart from the club I'm actually at.'
"Tottenham wasn't going to get done and someone else came in above them as well which would have caused a few stirs.
"If I would have said I wanted to go there for one minute my life at Man Citystaying there would have really tough for the next couple of weeks."
Asked if he was referring to Manchester United, Bellamy added on BBC Radio Five Live: "I ain't gonna say anything but it would have been a tough couple of weeks.
"It would have been a miracle if it had come off. I sat down with my agent and we were realistic, do we hold out for it or do I go on?
"And I think because of the other club being interested I think Man City panicked as well and said 'you can go to Cardiff' and they pushed it through as quickly as possible."