The England midfielder has been linked with a move to the Etihad Stadium in recent weeks.
Richards, 27, was speaking to Sky Sports at Villa’s official kit launch ahead of his first season in the Midlands, having left the Etihad Stadium to join Tim Sherwood’s side on a free transfer this summer.
New teammate Delph could soon be moving in the opposite direction, however, with City reportedly looking to take advantage of an £8 million buy-out clause inserted into the four-and-a-half-year deal he signed in January [h/t Telegraph].
According to the Telegraph, the England midfielder held talks with Sherwood last week about his future and, while he is settled at Villa, the prospect of Champions League football could prove too tempting for him to turn down.
Nevertheless, Richards has revealed that Delph has also sought his advice of late about a potential switch to the Etihad, with his advice being not to move without assurances of regular action.
The defender himself saw his opportunities with the Citizens limited in recent seasons and, having fallen off the England radar as a result, warns that the same thing could happen to Delph.
“If he's going to be playing Champions League... I don't know, but if he's going there to be a squad player, then no,” Richards told Sky Sports. "It's just being given that chance. If he [City manager Manuel Pellegrini] is going to give him the chance to play then it's hard to turn down the chance of playing Champions League football.
"To be fair he has asked me what I think about the situation. I told him I can't comment to be honest. I don't want to say go there and then he [Pellegrini] doesn't play him - he'll be ringing me up afterwards!
“It makes it difficult because next year is the Euros. If you go to Man City and find yourself only playing 10 games and someone [else] has a really good season that player is going to play for England. Things can change.
"Sometimes you've got to strike when the iron's hot and Delph is playing well but it's a difficult decision. I'm sure he'll make the right one."
|2014-15 Premier League||Position||Team||Goals||Assists||Total Key Passes||Passing Accuracy||Total Tackles GAME||Interceptions GAME||Total Dribbles GAME||Touches GAME||Appearances||Mins Played|
|Fabian Delph||MF||Aston Villa||0||3||36||85%||2.07||1.36||2.64||78.32||28||2,434|
Meanwhile, another release clause could lead to the departure of Villa’s other big-name star this summer, with striker Christian Benteke continuing to be linked with a move to Liverpool [h/t Telegraph].
The Belgium international’s signature is believed to cost a more substantial £32.5 million but, while it remains to be seen whether the Reds will opt to spend the required funds, Richards admits that his goalscoring impact would be tough for the club to replace.
"Benteke? I don't know,” he added to Sky Sports. “If he leaves it will be - not a problem - but he's one of the best strikers in the league. So it's going to be difficult if he leaves. But I think we've got a good group of lads. I've been impressed with the first two training sessions.
"I've obviously trained with the best at Man City and that's been really high, but the lads here are confident and hopefully we can take that into the new season."
Villa begin their Premier League campaign at Bournemouth on 8 August but, while Richards should be in the line-up for his claret and blue debut, it remains far from clear whether Delph and Benteke will both be there too.