Just a year after selling the striker to Chelsea for €115 million (£97.5m/$120m), he has brought him back to San Siro on loan for just €8m (£6.9m/$8.3m).
“There was fear in every moment [that it might not happen], because it was a very difficult situation that we’d never seen before: a player sold a year earlier for a price that we all know was going to be difficult," Lukaku's lawyer Sebastien Ledure told Sky Sport Italia.
Indeed, given the figures involved, it shouldn't have been possible to make his move happen.
But this is the very nature of today's transfer market, where nothing much makes sense anymore.
Barcelona, remember, are still effectively broke and yet are still optimistic about signing Robert Lewandowksi and Raphinha, while Richarlison is apparently worth £60m...
In many ways, though, Lukaku's return to Inter is the deal which perfectly sums up the modern game, containing, as it does, all of the elements of excess and absurdity that now define football...
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Paying players 'so much bloody money'
Covid-19 brutally exposed the fragile nature of football's financial model.
At the height of the pandemic, when wealthy Premier League clubs were availing of a government furlough scheme, a financial expert familiar with the accounts of several members of Europe's elite told GOAL, "From a business perspective, these clubs have always run very close to the wire in terms of the availability of cash. That has long been standard practice across the industry.
"But I don't know why that is. They don't need to, because there is an easy way out of that model and, to be frank, it's to stop paying the players so much bloody money!"
The financial crisis caused by Covid-19, then, offered a gilt-edged chance for everyone to take stock and implement meaningful change. That opportunity was not taken, as Kylian Mbappe's pay rise recently underlined.
Of course, the forward's employers, Paris Saint-Germain, were barely affected by the pandemic. Cash flow is not a concern for those clubs who have access to bottomless wells of oil money.
It is a major issue, though, for the likes of Real Madrid and Barcelona, who have been trying desperately to keep up with state-backed sides such as PSG and Manchester City over the past decade.
Rather than practice prudence, the old order have fought fire with fire, resulting in ridiculous, ever-increasing transfer fees and obscene player wages.
Inter have been far less reckless than some of their traditional rivals but the club's owners, Suning Group, pumped approximately €600m (£520m/$730m) into the club in just five years and were utterly ill-equipped to deal with the fallout from the pandemic-related economic crash.
Inter, along with so many other sides, most notably Barca, were thus hit far harder than they should have been by Covid-19, and paid a heavy price for living beyond their means.
Indeed, Antonio Conte knew his title-winning side was going to be stripped of at least two of its most important players, which is why he walked long before the sales of Achraf Hakimi and Lukaku.
It is also extremely telling that despite banking approximately €180m (£155m/$188m) from those two deals, Inter still need to balance the books.
They now have to sell another valuable asset this summer, most likely centre-back Milan Skriniar (to PSG, inevitably), underlining the gravity of their ongoing financial problems.
Instead, they'll probably all just continue to view the European Super League as an easy solution to their self-inflicted problems...
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The hasty exit and customary fan backlash
Given the state of Inter's accounts, they were never going to turn down such a massive offer from Chelsea for Lukaku.
Likewise, the player and his entourage were presented with the perfect excuse for jumping ship.
It wouldn't just be a good move for him financially, it would also boost the club's offers at a particularly perilous time...
However, it quickly became clear that Lukaku had wanted to leave once he became aware of Chelsea's interest.
Was he happy in Milan? Certainly. One cannot under-estimate how much he enjoyed and embraced his Serie A experience.
But there was an obvious, and perhaps, understandable desire to belatedly become a star at Stamford Bridge, having failed to score during 15 previous appearances for Chelsea between 2011 and 2014, while at the same time proving a lot of Premier League followers wrong in the process (probably Gary Neville for starters!).
Inter fans may have been more understanding, though, had he not just upped and left without saying a word, and even Lukaku subsequently admitted that he had handled his departure dreadfully.
After all, he had expressed his commitment to Inter just weeks before, stating he was looking forward to the new season, making the usual bitter fan backlash absolutely inevitable.
A matter of hours after he had flown out of Milan's Linate airport, his mural outside San Siro was defaced, while the Curva Nord ultras issued a vicious open letter to the self-titled 'King' of Milan.
“Dear Lukaku, we expected more honest and transparent behaviour from you," it read. "But, despite the fact we protected you like a son, like one of us, you too proved yourself to be just like all the rest, going to your knees for money.
"We wish you the best, even if greed doesn’t always pay."
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Transfers without a thought for tactics
Bringing Lukaku back to the Bridge certainly didn't pay off for Chelsea. Seriously, what were they thinking?
The reigning European champions were seemingly so preoccupied with whether or not they could re-sign Lukaku, they didn't stop to think if they should.
How else to explain the decision to break their transfer record to sign a striker so unsuited to Thomas Tuchel's style of play?
And Chelsea have previous in this regard, remember: many expensive centre-forwards have flopped in west London, with fans long fearing 'The curse of the No.9 jersey'.
Nonetheless, in their desperation to sign a prolific striker, the Blues turned to a player that had primarily thrived at Inter because Antonio Conte was so willing to play to Lukaku's strengths.
Tuchel was not, of course, and, reportedly even joked about the forward's close relationship to Conte, only for Lukaku to fail to see the funny side.
Whatever the truth, Lukaku undeniably more and more disconnected, on and off the field, as the season wore on.
As a result, he now features twice on a rather ignominious list of football's most expensive flops, one which hammers home the point that many of the biggest deals in history have been a complete waste of money due to a total lack of foresight.
The killer PR disaster-class
In an era in which simply unfollowing a social media account can provoke wild speculation, deciding to speak so openly about his struggles at Chelsea and enduring love for Inter effectively represented the nuclear option.
It's hard to know exactly what the goal was, or why it was thought that an unsanctioned interview would be a good idea.
Lukaku is not happy at Chelsea 😬 pic.twitter.com/tEWAVNzsv7— GOAL (@goal) December 30, 2021
Perhaps Lukaku's people thought it might place a little pressure on Tuchel to modify his game plan, while at the same time mending his relationship with Inter supporters.
The net result, though, was scorched earth.
Tuchel dropped him for Chelsea's next game, against Liverpool, some supporters booed him when he eventually returned to the starting line-up, while Inter's ultras again issued a withering reply to his actions: "It doesn’t matter who runs away in the rain, it matters who stays in the storm. Bye, Romelu."
With one ill-advised interview, Lukaku had managed the unprecedented feat of p*ssing off the supporters of his former club and his current club at the same time, meaning he ended up having to issue two grovelling apologies in less than one week.
The obligatory social media cringe-fest
These days, no major transfer would be complete without a cringeworthy social media post and the best thing one could say about Steven Zhang's video reveal with a clearly uncomfortable Lukaku earlier this week is that it was fittingly awkward.
There were an impressive amount of lowlights in such a short space of time but the most amusing exchange was when Zhang asked Lukaku if Inter were going to score a lot of goals at San Siro this season.
"That's what we're here for," Lukaku replied. "You promise?" Zhang asked.
"I keep my promises," Lukaku claimed, immediately provoking ridicule across social media, given the way in which he had walked away last summer.
His habit of constantly kissing the crest of whatever club he's playing for was also brought up to suggest a lack of loyalty on Lukaku's part.
He'd hardly be alone in that regard, of course. Indeed, Robbie Keane constantly signing for his 'childhood club' immediately comes to mind, as does Snoop Dogg supporting pretty much every club in Europe at one time or another...
Instant forgiveness by fickle fans
The bottom line is that Inter arguably need Lukaku as much as he needs them. They certainly have a better chance of reclaiming the Serie A title from city rivals AC Milan with Lukaku back in the team.
Simone Inzaghi knows this only too well. The Inter boss only got to work with Lukaku for a few weeks but has privately described him as one of the best players he's ever coached.
The pair remained in touch touch throughout the entire 2021-22 campaign – doubtless another source of disbelief and outrage at Chelsea, who are still paying his wages, remember – and the same goes for Lukaku and his Inter team-mates, revealing that he'd been giddily texting all of his "brothers" for the past month.
However, while he will be warmly received in the dressing room, Inter's ultras obviously were less enthused by Lukaku's return, urging their fellow fans to avoid going to greet the prodigal son with scarves and banners.
That plea fell on deaf ears, though.
Still, even the ultras admitted that while they had lost respect for Lukaku because of "last summer's behaviour", they weren't going to object to his arrival and said they had no intention of booing him.
There was instead a clear implication he could regain their support – if not their love – with "humility and sweat" on the field.
And that is not in the least bit surprising in a footballing world where winning is all that matters, meaning a player's past indiscretions can be conveniently overlooked in the ruthless and incessant pursuit of success.
It's a shame, of course. Genuine idols are rare in modern football. But Lukaku had carried himself like a king in Milan, and was treated like one.
Unfortunately, as the club's ultras pointed out, he is now "just like all the rest", a willing pawn in a money-obsessed modern game driven by ever-more expensive transfers that make little sporting sense.