There are, of course, many things to still sort out, the main one being that Juventus are demanding a transfer fee for Ronaldo, which City are not keen to abide by.
However, you get the feeling that that issue stands a very good chance of being resolved and that means the idea of the Portuguese superstar in a sky blue shirt is a distinct possibility.
If it does happen, Manchester United fans will be fuming and it's easy to understand why.
Ronaldo spent six years with the Red Devils and won the first of his five Ballon d'Or awards while at the club.
To put it simply, he's a United legend and that's why a move to City this summer would be a hugely controversial one.
The transfer wouldn't be the first to fit into that category, though.
There have been many controversial high-profile moves in football down the years and in 2020, the folks over at ESPN named their top 10 in that regard.
So, shall we take a look at the publication's picks for the most controversial transfers in history?
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10. John Obi Mikel to Chelsea
A truly bizarre transfer. In 2005, both Manchester United and Chelsea announced that they had agreed a deal to sign the Nigerian midfielder, a situation which resulted in FIFA getting involved. Mikel was then asked to decide who he wanted to play for and he chose the Blues. Unfortunately for the West London club, they had to pay United a cool £12 million in compensation. Ouch.
9. Carlos Tevez to Manchester City
Prior to his move to City in 2009, Tevez had spent two years on loan at the team's bitter rivals United. The Red Devils apparently wanted to sign the Argentine permanently, but it never happened and City swooped in. The 'noisy neighbours' then put up a billboard of Tevez with the phrase "Welcome to Manchester" on it, just to rub salt in the wounds.
8. John Robertson to Derby County
The transfer that ended the relationship between famous duo Brian Clough and Peter Taylor. The pair enjoyed a huge amount of success together at Nottingham Forest, before Taylor opted to manage the club's fierce rivals Derby County in 1982. A year later, Taylor signed Robertson, who's one of Forest's greatest ever players, and he did so without informing Clough. The two never spoke again...
7. Robin van Persie to Manchester United
This century, Arsenal fans have had to watch a number of their star players sign for a rival club. Van Persie's move away hurt the most, though. In 2012, the Dutchman was arguably the best player in the Premier League and Gooners were hopeful he'd stay in north London. Spoiler alert, he didn't and his £24 million move to United helped Sir Alex Ferguson win another league title.
6. Ashley Cole to Chelsea
It's Arsenal again. Chelsea 'tapped up' Cole back in 2005 while he was in a contract standoff with the Gunners and Jose Mourinho's approach was even declared illegal by the Premier League. But all the fines and uproar still didn't prevent Cole from controversially moving to Stamford Bridge, with William Gallas going in the other direction.
5. Johan Cruyff to Feyenoord
What's the best way to get back at a club that think you're 'finished' and 'overweight'? Sign for their biggest rival. That's exactly what Cruyff did in 1983 during his second spell at Ajax and in his one season with Feyenood, the Dutch legend won the double and was named the country's Footballer of the Year. Now that's what you call revenge.
4. Roberto Baggio to Juventus
Baggio's then world-record £8 million move to Juventus from Fiorentina was so controversial that it sparked riots in Florence. Then in a game between the two clubs after the transfer, Baggio picked up a Fiorentina scarf that had been thrown on the pitch after being substituted. Unsurprisingly, the gesture didn't go down well among Juve fans...
3. Sol Campbell to Arsenal
Tottenham fans will never, ever forgive Campbell. Why's that? Because the defender kept hinting that he would stay at Spurs, before then completing a free transfer to Arsenal in search of trophies and Champions League football. It may just be English football's greatest act of betrayal and even Ronaldo's move to City wouldn't top it.
2. Luis Figo to Real Madrid
You have to be a very brave man to cross the El Clasico divide. Figo took the risk in 2000, joining Real Madrid from Barcelona after his £38 million release clause was activated. Barcelona fans were livid that their best player had joined the team they hate most and it culminated in them throwing a pig's head at the Portuguese winger when he returned to Camp Nou in 2002.
1. Mo Johnston to Rangers
In 1989 after two years with Nantes, Johnston appeared to be close to a Celtic return, the club where he'd enjoyed a lot of success. The move collapsed at the last-minute, though, and Johnston opted to join Rangers instead. Celtic fans were outraged and the Rangers faithful weren't happy either, as the striker was the first high-profile Catholic to openly play for club. Angering both sides of a rivalry? Now that really is something.