City brought Trafford back from Burnley for approximately £27M after an impressive Championship campaign and he started City's opening three Premier League fixtures.
However, after the club brought in Gianluigi Donnarumma from PSG on transfer deadline day, Trafford was restricted to cup appearances as his dream move quickly crumbled away.
Trafford eventually left City to join Leeds United in a deal worth up to £45M as he left the club with a number of trophies, but also a feeling of failure and of being unwanted.
Speaking to the BBC this week, the England star has revealed that he struggled during his time with the Citizens as he was pushed aside by manager Pep Guardiola.
"What a horrendous, horrendous feeling. Not playing. You are ringing a lot of people and just venting. Like most people, you have a (bad) day at work and you ring someone up.
"I ring my dad, I ring my mum, I ring my missus, I ring my mates. I like ringing my mates and we can just have a good talk about it all. It's quite funny.
"I had to play regularly this season for my own mental wellbeing. You just lose yourself not playing. Maybe I'm different, I don't know, but the feeling of not playing every week, it felt horrendous.
"I just had to play every week this season for that mental feel-good and to keep progressing with my career and edging me closer to achieving the dreams I want to achieve."
He also stated: "There were moments when I was very down, regretting things and feeling disappointed, but looking back, I'm very thankful for the experience. What an incredible year."
Trafford has started all nine of Leeds' Premier League matches this season, keeping three clean sheets as he picks his career back up.