Richards did not feature in City's first six games of the season after, he has now revealed, suffering a hamstring injury on the eve of the opening match against Newcastle.
It was the latest in a number of setbacks for the 25-year-old, who missed most of last season under Roberto Mancini due to ankle and knee problems.
The 25-year-old returned to action as he was named captain for the Capital One Cup third-round tie against Wigan at the Etihad Stadium.
Richards told the club's matchday programme: "I think pre-season took its toll because we had a lot of games and there was a lot of travelling, and whereas some of the guys are fine, being a bigger lad, it takes my body maybe a couple of days longer to recover.
"Under Roberto Mancini, the intensity in training was a little lower - that's not a criticism of Manuel Pellegrini's methods - it's just that the workload has increased and it's going to take the players time to get used to it.
"We'll get used to it and ultimately it's to our benefit because we'll get fitter and stronger as time goes on."
Richards excelled in the right-back position during City's Barclays Premier League title-winning season of 2011-12 and he believes that position is probably where his future lies.
He said: "We have some great central defenders at this club with Vinnie (Kompany), Matija (Nastasic) and Joleon (Lescott) and we also have Martin Demichelis now, too, so I can't see a time where I'll really get a good run in central defence.
"I think right-back is where I need to concentrate on playing for the time being."
Last season's injury problems, which limited him to just eight appearances, denied Richards any chance of forcing his way into the England set-up under Roy Hodgson.
Richards, who had been consistently and controversially overlooked by Hodgson's predecessor Fabio Capello, now fears his chances of returning to the international scene for the World Cup - if England qualify - are limited.
He said: "I can't help thinking that, unless there are injuries, it probably won't happen.
"It's all about opinions and I hope Roy Hodgson will give me the chance to force my way into the squad.
"Picking up niggling injuries isn't helping my cause so I need to keep fit, do my best and see what happens."