The 23-year-old underwent an operation shortly after and has been recuperating ever since.
Now, as City enter the final third of the campaign, the French left-back is steadily upping his recovery programme and now has firm targets in his sights.
“When I started my recovery, I had in mind the semi-finals of the Champions League,” says Mendy with a glint in his eye.
“That was my goal, but I am coming back a bit quicker than expected originally so maybe it will be possible for me to return sooner than that. I believe in this.
“I think it’s possible for me to come back within four weeks. It’s not a good thing to come back too soon and you have to take your time.
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“We will see how things go, but I am working hard and optimistic.”
Mendy, who has built up a cult following via his social media channels believes he could be back at the start of April if things go well.
That could mean a dramatic return against United – but even if he doesn’t make it for that game, he is hoping it will be able to enjoy the season’s run-in with more silverware still up for grabs.
And Mendy needs just one more Premier League appearance to qualify for a Premier League title medal – should the Blues successfully negate the remaining fixtures and win the five games needed to be crowned champions.
“The Manchester derby is a realistic aim. That’s half clear in my mind. I really want to play that game," he said.
“Of course, there is the World Cup on the horizon, too. For me, there is no doubt regarding the World Cup.
“After I return, it’s on me to impress; I have to make sure I come back well and to keep the rhythm. Before it was one of my targets, but now I know it will be fine.”