COMMENT: So, Jadon Sancho to Manchester United? For 100 million quid? At 18 and after barely six months of decent football. Just like that. United are going to break the bank on a promise? On potential...?

At first flush, this story looks a floater. Sancho has just signed a new deal with Borussia Dortmund. Extending the previous agreement by two years to 2022. But now, so they say, less than four months on he's going to chuck it all in and return to Manchester...

But Dortmund do have previous. They thought nothing of cashing in on Ousmane Dembele when Barcelona came knocking two summers ago. A year after paying €15m to Rennes for the French whizkid, BVB were selling him for a fee rising to €140m. Sancho would arrive from Manchester City for a cut-price €10m and inherit Dembele's No7 shirt. Is it really so fanciful that a Dembele-type move could be the next step in the teen's career?

But that's the problem. And it's the feedback this column gets when asking around about Sancho. He's always moving. At 14, Watford wasn't enough so he headed north to Manchester. Less than four years later and City couldn't give him what he sought, so he upped sticks and left for Germany. And now, two seasons after landing in Dortmund, they're saying he wants out again.

Some would say he's ambitious. Driven. But you do it so often and you become little more than a gun for hire. No connection to a club. To a support. Think Christian Vieri. Or closer to home, Robbie Keane. Great players. Great careers. But who do you associate them with? Their national teams, sure. But that's it. And there should be more to a footballer's career than that.

When recalling the first time he set eyes on Sancho, World Cup winner Lothar Matthaus joked: "I called my manager to tell me who he was and where he came from. Five minutes later the SMS returned: 'Sancho, Manchester City'. I called him and told him that if he signed him, he could make a lot of money. I had only seen him play for ten minutes..."

This was lighthearted from Matthaus. A few throwaway lines. But there is an element of deeper truth in his words. Everyone wants a piece of Sancho. And it's been that way long before he popped up at Westfalenstadion.

It can't be coincidence that in the same week we're hearing of United actively discussing a move both Arsene Wenger and Jurgen Klopp spoke publicly about their attempts to sign Sancho for Arsenal and Liverpool respectively. As we say, they've all wanted a piece of this kid.

Matthaus again: "To get him for such little money from the reserves in England, is like winning the lottery. He not only helps Dortmund, he also helps the Bundesliga beyond our borders. In England, the Bundesliga is gaining in importance, now he is their national player."

So he's not only carrying BVB on his shoulders, but also front and centre for the Bundesliga's global push? What are we talking about here?

Thomas Delaney, the Danish midfielder, sought to ease the hype around his BVB teammate last week, castigating the English press for exaggerating Sancho's on-field progress thus far.

"He's a rough diamond and he'll get there," said the Dane. "I feel a bit of responsibility for keeping him on the ground because I know, now we are here in England, you are world famous for hyping your own players."

Wise words - and spoken with authority. Delaney, like his teammates, will have witnessed first hand the frenzied interest Sancho has been generating.

Michael Zorc, BVB's general manager, just days ago revealing: "Over the past few weeks, 30 English journalists have been here.

"We've even had the New York Times visit us."

To Zorc's credit, he has insisted Sancho will remain a Dortmund player next season. Both he and fellow powerbroker Hans-Joachim Watzke have never apologised for their buy low sell high transfer model. But in Sancho's case, there is a determination to see this project through.

"Jadon Sancho will stay with us in the next season," declared Zorc last month. "He has great quality and is a bet for the future, he will remain in Dortmund."

Which would be the best thing for the kid. For his career. And particularly for his reputation. Sancho needs to put down roots. Build a relationship with fans. Play for them. And what better support to play for than the Yellow Wall?

Earlier this season, Sancho spoke of his pride at sharing the pitch with Wayne Rooney on his farewell international with England. It took Sir Alex Ferguson three attempts to convince Rooney to leave Everton for United back in 2004. At 14 and at 16, Rooney turned them down. Eventually Ferguson would get him at 18. And that loyalty shown to Everton as a junior would translate to Rooney's commitment to United as a senior player.

There's something to admire about the ambition of Sancho. To push himself beyond the norm. But in this industry. In this sport. There's also loyalty. Relationships. If United do come calling, Sancho should think twice before skipping out on another club this summer.

He only need ask Rooney. If Sancho maintains his progress, United will be back. Again and again.