The centre-back moved to Villa Park in 2007, making the short journey across the West Midlands from West Brom.
He initially settled well and was regularly touted as a potential England international of the future.
However, things started to unravel last season, with a shoulder operation not helping his cause, and he soon found himself out of favour.
He has gone 14 long months since he last appeared in a Premier League fixture, with former Villa boss O'Neill having overlooked him at every opportunity.
Davies has recently linked up with Championship side Leicester on loan in an effort to get regular games and is enjoying his football again.
He does, however, admit that he is almost starting from scratch after becoming the forgotten man at Villa Park.
"My career's not just stalled massively, it's slowly come to a stop," Davies said after making his Foxes debut against Hull City on Saturday.
"People describe me as lacking form, but how can you have a lack of form if you don't have any games?
"I wasn't allowed on loan in January and was kept as a spare part basically.
"Promises were broken. To be cast aside was a bitter pill to swallow.
"I didn't want to leave the club. I wanted to go out on loan, get games, then come back and fight for my place.
"I was told I was next in line for a game, but that usually means on the bench, not watching games at home on Sky."