The 23-year-old went from being the player of the year at City for the 2008/09 season to playing little part under Mancini or his predecessor Mark Hughes last term.
Ireland, who joined Villa as part of the deal that took James Milner to City, dismisses claims he had a suspect attitude.
He said: "I thought that was really unfair. I was first in and last out of training and no-one worked any harder than me.
"I was always the best player in training so maybe I was not for him. For the last year or two it wasn't easy to operate.
"If I had left two or three years ago it would have been more difficult than now. Leaving now it seems as if I was never at City."
Source: PA
Source: PA