Neil Humphreys: Spurs can't afford to lose Dier
Tottenham have bought no one of note so Pochettino must hold on to his best players
Daniel Levy must be eyeing Manchester United's offer like a starving mouse staring at cheese on a trap.
The Tottenham Hotspur chairman knows that selling Eric Dier would be risky, perhaps even fatal.
But £50 million (S$89m) for an unsettled midfielder is one hell of a chunk of cheese.
And, when it comes to the transfer market, Levy's a giggling kid with a Monopoly board.
But, in this instance, United's interest in Dier isn't a game. It's a mousetrap.
For Tottenham, selling Dier would be tantamount to English Premier League suicide.
And yet, the temptation to sell remains as the sense of unease grows around the White Hart Lane building site.
Spurs have money troubles. Levy anticipates a season of austerity. The club's initial £400m cost estimates for the new stadium have ballooned to £800m.
Tottenham must accept a sustained period of belt-tightening, a draining experience at the best of times, but to cash in on Dier's restlessness and United's recklessness would be disastrous.
Levy had just about shaken off his wheeler-dealer reputation for maximising profits by flogging the likes of Gareth Bale and Luka Modric.
The guy who once basked in the heat of transfer windows had reined himself in.
Tottenham are no longer a "selling club".
Harry Kane, along with Mauricio Pochettino's other pretty young things, were reportedly not for sale at any price as Spurs prepared for a third assault on the title.
However, doubled stadium costs appeared to have halved the ambitions.
Pochettino has bought no one of note. Tottenham are rarely linked with anyone, making headlines only when another jittery employee seeks an early exit.
According to reports, Pochettino must balance the books, rather than the squad.
The Argentinian appears ready to benefit from Manchester City's belief that Kyle Walker is worth £50m and the right back could head north.
If Dier follows Walker on the road to Manchester, he'll take Tottenham's hard-earned momentum with him.
London clubs finished first and second last season, an unpalatable state of affairs for the football powerhouses up north. A couple of key transfers could easily see the balance of power return to Manchester.
Of course, there's no doubt that Dier suffered a rather Dickensian tale of two seasons.
His outstanding 2015-16 campaign ended with a starting place in England's Euro 2016 line-up.
But the Euro 2016 debacle seemed to infect Dier's subsequent performances, as if he had caught the virus of anti-climax that afflicts so many in England jerseys.
Last season, Dier lost his place to Victor Wanyama, another Pochettino protege that morphed into a midfield beast at White Hart Lane.
The Kenyan offered reliable attacking versatility, the hallmark of Pochettino's swift, counter-pressing.
Dier struggles with the perception of being a more conventional defensive midfielder, a rather simplistic description of his attributes.
He's only 23 and still learning. He's hardly set in his ways, a pair of stubborn boots encased in concrete just outside the penalty box.
Dier can adapt, improve and find a more fluid role in Pochettino's plans. From Tottenham's point of view, he must.
Mourinho loves defensive midfielders. He covets them at every club.
From Porto's Costinha in 2004 to United's Ander Herrera in 2017, Mourinho has rarely won a European final without one.
The incorrigible pragmatist feels naked without a defensive midfielder, exposed to the unpredictable attitudes of rampant counter-attackers like Pochettino's charges.
As United's interest in Nemanja Matic declines, the temptation to improve their offer for Dier only increases. The Englishman clearly ticks Mourinho's boxes.
He's defensive-minded and favours a fixed position. More importantly, he's ambitious, unsettled and playing for a club with mounting stadium debts.
United have been here before with Arsenal and Robin van Persie. The Red Devils got their man and won the title.
Spurs are at risk of repeating history of the most unwanted kind.
If Dier leaves, the early title momentum will immediately swing from London to Manchester, encouraging others to shy away from Spurs and join Mourinho's revolution instead.
Most of all, Tottenham will look like Arsenal.
And that would be a truly Dier state of affairs.