Some clubs have managed the transfer market especially well in recent years (Real Madrid, Manchester City and Liverpool have led the way), while others have struggled to match up (namely Barcelona, Manchester United and Chelsea.) But sometimes there is little they can do, as it is the players who hold the power.

July 1 marks the moment when stars including Tottenham striker Harry Kane, Man United forward Marcus Rashford and Paris Saint-Germain's Kylian Mbappe get to take control, as they will have 12 months left on their contracts. In Europe's major leagues, contracts run from July 1 to June 30, so there will be many top performers -- including United goalkeeper David de Gea, Liverpool's Roberto Firmino, Juventus midfielder Adrian Rabiot and Borussia Monchengladbach forward Marcus Thuram -- who officially become free agents at the weekend, without having already agreed to join another club.

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But for those who are entering the final year of their deals, there will be a real power shift in their favour. Kane and Mbappe, leading targets for some of the biggest clubs in the game, could use their dwindling contract status to force moves away from their present employers.

One of the world's most exciting young players, Mbappe has until July 31 to trigger a one-year extension to the contract he signed in 2022 when he snubbed a free transfer to Real Madrid. But the France international claims he won't put pen to paper and, while he's happy to stay in Paris for another year, he will be looking to depart for free.

Sources have told ESPN that said PSG chairman Nasser Al-Khelaifi is begrudgingly open to letting the 24-year-old leave this summer, but wants a transfer fee in the region of €150 million ($163m). Few (if any) clubs will pay that, and the fee will come down the longer the saga plays out.

It is a similar story with Kane. Though he has yet to openly express a desire not to extend his contract at Tottenham, which also expires in 2024, club chairman Daniel Levy knows he is running out of time to persuade the England striker to stay.

In the summer of 2021, Levy faced down Manchester City by refusing to even negotiate unless they offered a transfer fee of £150m to sign Kane. City walked away, bided their time and landed Erling Haaland for £52m from Borussia Dortmund 12 months later.

Two years ago, Levy and Spurs were in a position of strength; Kane had three years to run on his contract and the value for the club was to keep him rather than cash in by offloading him. Now, the dilemma is to decide whether one more season of Kane is worth more than taking a fee that would approach £100m this summer. If Kane makes it clear that he will leave as a free agent next summer, Levy has until the window closes on Sept. 1 to decide whether he takes his last chance to cash in, or accept that his star player could walk out the door for nothing.

Spurs and Levy, publicly at least, have yet to make their decision on Kane, while United have made it clear they are committed to sealing a new deal for Rashford. The 25-year-old is not openly courting a move away from Old Trafford, but the prospect of him going into the 2023-24 season without committing his long-term future to the club will be one that worries them given his 30 goals in 56 games last season.

Few leading players take advantage of their ability to negotiate a free transfer with overseas clubs in the January transfer window. But PSG, Spurs and Man United know that they're losing a grip on their stars with every month that passes without them committing to a new contract.

As soon as the calendar flips into July, the pressure increases. Clubs have two months to turn the situation to their favour, as what little influence they have now will be gone by the time January arrives. It's a situation you will see across Europe as the transfer window edges towards a conclusion.

Chelsea's Mason Mount wants to run down his contract after failing to agree to new terms, but his club have rejected three bids (the latest of £55m) from Man United to sign the England midfielder as they hold out for £70m. It's a dangerous strategy for the Blues, as United could turn their attention elsewhere.

West Ham chairman David Sullivan said after their UEFA Europa Conference League final win that he has agreed to let midfielder Declan Rice depart, despite the club having a one-year option to extend his deal until 2025. But they have already turned down two bids from Arsenal (the last of which was £90m total, comprising of £75m plus £15m in add-ons) as they want more than £100m.

Manchester City recently rolled the dice on midfielder Ilkay Gundogan and lost, with the 32-year-old midfielder choosing to join Barcelona on a free when his contract expired this summer instead.

So will Tottenham and PSG put finances first by granting Kane and Mbappe a move? Will United pay Rashford more than they really want to avoid the saga of him running down his contract, as Paul Pogba did before returning to Juventus 12 months ago?

The answer to those questions is likely to change in the weeks ahead based on the actions of the players involved, because the clubs no longer have the control. Suffice to say, the clock is ticking.