Richards made just eight appearances in the 2012/13 season and only ten the season later and the defender admitted he knew his City career was over leading to dark times.
"That was dark for me," he told the Gloved podcast.
"I'd lost my place to Zabaleta because he'd been unbelievable and I'd been injured for eight months.
"I knew, deep down, unless Zabaleta got injured – I wasn't getting my place back.
"That's just me being honest, because he was so firmly in that team.
"The season I got injured, he got nominated for player of the year, he was amazing in the cup, everything he touched turned to gold.
"When he got in and stayed in, the way he was playing - I knew I wasn't getting back in."