The Guardian's Jamie Jackson reported Kevin De Bruyne is being pursued by Manchester City in a reported £47 million deal, so the inevitable questions are being asked.

Why did Chelsea sell him? Should manager Jose Mourinho have given him more time to prove himself? Did the club make a mistake in allowing De Bruyne to leave when he did?

The answer is no.

In the six months he spent at Chelsea after loan spells at Genk and Bundesliga side Werder Bremen, De Bruyne did very little.

In fact, he did nothing.

His time at Stamford Bridge was one of frustration for club and player. De Bruyne didn't seem to fit into Mourinho's system and, in the nine appearances he did make, didn't seem as though he wanted to.

Of course, that's a perspective from watching events unfold from afar, but De Bruyne didn't have the look of a player who was ready and willing to adapt or fight for his place at Chelsea.

And often, the body language can tell us plenty.

De Bruyne offered so much promise. His time developing at Genk had put him on Chelsea's radar, with the form De Bruyne produced in his 12-month spell with Werder Bremen reinforcing what we'd seen with the Belgian national team.

He was exciting; De Bruyne seemed a talent to complement what Chelsea had, particularly his compatriot Eden Hazard.

In practice, it never worked. Mourinho couldn't get what he wanted from De Bruyne, who in turn struggled to reproduce the sort of form that had convinced the manager another loan move wouldn't be suitable, that he was ready to be a Chelsea player

De Bruyne flopped.

His performances aren't the issue, though. It's what came after De Bruyne that is important to consider from a Chelsea perspective.

That the Belgian has relaunched himself in the Bundesliga for a second time is irrelevant. That Manchester City now value him close to £50 million, even more so.

Without De Bruyne, Chelsea are stronger.

The club made £55.1 million in player sales in January 2014, selling Juan Mata and De Bruyne for significant profit.

Mata joined Manchester United for £37.1 million, and De Bruyne moved to Wolfsburg and back to the country that had served his development so well less than a year earlier.

The funds Chelsea received meant Mourinho could rebuild this Chelsea squad more in his vision—the exact vision that delivered the Premier League title last season.

Until Mourinho's return, Chelsea's transfer policy had lacked any real cohesion. Aside from the positives of exploiting the loan system with youngsters, there was a tendency to buy players in bulk for certain positions, notably attacking midfield.

The Stamford Bridge dressing room was bursting with No. 10s, or those purporting to be such. There was an imbalance.

Given Mata had twice been voted Player of the Year at Stamford Bridge, it was a surprise that he was culled in Mourinho's shake-up.

De Bruyne made sense, however.

Signed as part of Chelsea's aforementioned approach in buying up young talent from across the globe to channel through the loan system, De Bruyne is the flag bearer for the system's success.

Then aged 20, De Bruyne cost just £7 million in January 2012. Two years later, and with minimal additional investment from the club, his sale was bringing in an £11 million profit—profit that has since been used wisely.

No sooner than De Bruyne joined Wolfsburg for £18 million, Chelsea had added Nemanja Matic and Kurt Zouma to their squad.

Matic made an immediate impact. Returning to west London after his departure to Benfica in January 2011 as part of the David Luiz deal, he was the defensive midfielder Mourinho had craved.

The entire dynamic of Chelsea's defensive lineup was improved before the ink had dried on his new contract.

Six months down the line, Zouma was added as a full-time member of Mourinho's first-team squad after having spent the remainder of 2013/14 on loan with the club that had sold him, Saint-Etienne.

Last season proved a breakout one for the Frenchman, reinforcing the options Mourinho has in key positions.

Follow the money trail, and the sale of De Bruyne makes sense, especially when combined with Mata's exit.

Matic and Zouma cost Chelsea £21 million and £12 million, respectively. Without those sales, those moves probably wouldn't have happened.

A decade ago, maybe; but in these times of sound financial planning, Chelsea's business model is much more pragmatic. Mourinho has to sell before he can buy; the books must always be balanced.

De Bruyne has been an ideal pawn in making that work without proving detrimental to the team.

Even considering the fact Chelsea signed Mohamed Salah for £11 million in the same transfer window, Chelsea were still another £11 million in the black.

It was a remarkable transfer window for Chelsea—one that put Mourinho's squad six months ahead of their rivals when it came to planning for the summer.

Adding Diego Costa and Cesc Fabregas just before the World Cup, it was clear we were looking at the 2015 Premier League champions.

The Spanish pair completed the puzzle, but without the sale of De Bruyne and Mata, it would never have been the case. There would have been more transfers to make, more negotiations to be had.

Those sales formed part of the bigger picture in the mind of Mourinho. The plan delivered.

The moment De Bruyne departed Stamford Bridge, Chelsea lost control of where his career could take him. That was down to the player himself, and when we consider the past 18 months he's enjoyed at Wolfsburg, he's certainly made the most of it.

What Chelsea did control was how they spent the money they generated from De Bruyne; how they strengthened and how they transformed the club from also-rans to champions.

After a dismal spell in west London, De Bruyne wasn't a £50 million player. Indeed, there's a debate as to whether he is or isn't now.

Chelsea's profit from De Bruyne remains significant. It's been reinvested to help deliver the Premier League and Capital One Cup, so why should Chelsea carry any sense of regret?

When he lifted the Premier League trophy in May, Mourinho wouldn't have been thinking about De Bruyne. And whether or not De Bruyne joins Manchester City, the Chelsea boss won't have him on his mind now.

Players come and go at any football club.

Garry Hayes is Bleacher Report's lead Chelsea correspondent. All quotes were obtained firsthand unless otherwise noted. Follow him on Twitter @garryhayes.