It’s an unthinkable scenario for the tribal upper reaches of the Premier League.

In a competition where Serbia defensive midfielder Nemanja Matic’s defection last August to Manchester United from Chelsea is a rarity, what would happen if open season erupted and the top six could pick up one player from their immediate rivals?

We’ve had a go at imagining how this would look.

MANCHESTER CITY

Eden Hazard (Chelsea)

How can you improve on perfection? This is the challenge that awaits boss Pep Guardiola after City’s record-breaking charge to last term’s Premier League title.

You have to be a special talent to improve an attack that struck 106 times in the Premier League. Chelsea’s Belgium forward Hazard would fit this billing, perfectly.

The 27-year-old could not hide his exasperation in 2017/18 about manager Antonio Conte’s constraining tactics.

Guardiola would grant him this freedom – and we saw how this worked out when the Spaniard had Argentina icon Lionel Messi under his aegis at Barcelona.

MANCHESTER UNITED

Marcos Alonso (Chelsea)

Chief among manager Jose Mourinho’s problems to solve this summer is his options at left-back.

England’s Luke Shaw and Netherlands’ Daley Blind have come up short of requirements, while current incumbent Ashley Young is a 32-year-old reformed winger.

This is where Chelsea’s Marcos Alonso comes in.

He’s got everything ‘The Special One’ wants in a full-back – diligent in the tackle, adds height to the backline plus is economical in attack as a combined 13 goals and five assists details in two Premier League campaigns.

Mourinho oversaw the sale of the then 19-year-old to Bolton Wanderers during 2010’s first summer at Real Madrid. He’d now relish making the opposite move.

TOTTENHAM HOTSPUR

Hector Bellerin (Arsenal)

It’s a difficult task to improve a Spurs starting XI that is arguably only bettered by City’s champions.

But one area that isn’t truly settled is at right-back, where England’s Kieran Trippier and Ivory Coast’s Serge Aurier do not always fully convince.

A glance across north London would take in Bellerin.

There is no doubt that the rampaging Spanish right-back has regressed since 2015/16’s startling breakthrough. But this is where the fabled coaching abilities of Mauricio Pochettino come in.

A player who has been clocked running faster than Thierry Henry and Theo Walcott has a special gift. The Argentine would be able to eradicate the defensive frailties all too often apparent – see Diego Costa’s goal in the Europa League semi-finals for a contemporary example – and accentuate his attacking gifts.

What a prospect that would make the 23-year-old.

LIVERPOOL

David De Gea (Manchester United)

The Reds’ long-term failing between the sticks came back to bite them in painful fashion during last weekend’s Champions League final defeat to Real Madrid.

A pair of unfathomable mistakes from German Loris Karius ensured a new goalkeeper must be sought this summer.

If money was no object and rivalry could be pushed to one side, then there is no better candidate than bitter rivals United’s Spain No1.

De Gea is simply without compare in the Premier League – if not the world.

In 2017/18, United had the second-best defence (28 goals conceded). But the busy De Gea was forced to make the fifth-most saves (115).

This a feat way beyond the abilities of Karius and Belgium No2 Simon Mignolet.

CHELSEA

Harry Kane (Tottenham)

Last summer’s addition of Alvaro Morata was meant to provide a seamless transition from fellow Spain centre forward Diego Costa.

A bright start that contained seven goals in his opening eight matches pointed to a new dawn at Stamford Bridge.

This was not to last. Morata struck just three times during the season’s final 23 matches, a stark decline that saw him miss out on La Roja’s squad for World Cup 2018.

One lethal striker who will be present in Russia is England and Tottenham’s Kane.

The 24-year-old is in a league of his own when it comes to judging front men. A tally of 108 goals in 150 top-flight games for Spurs speaks for itself, while he also offers a physical factor redolent of Blues great Didier Drogba.

ARSENAL

Vincent Kompany

There are finer centre-backs currently plying their trade in the Premier League than the 32-year-old version of Vincent Kompany – fellow Belgium stars Jan Vertonghen and Toby Alderweireld immediately spring to mind.

But there is something the elder statesman possesses in spades that is a rare commodity – genuine leadership skills. This facet has been glaringly absent at Arsenal since the exit of France’s William Gallas in 2013.

Kompany remains a true guiding light and inspirational presence, even if years of nagging muscle injuries have chipped away at his physical prowess.

His influence could bring out the best in erratic Germany centre-back Shkodran Mustafi, whose abysmal second half of 2017/18 cost him a place in the World Cup squad.