Chelsea took a bit of a step back in 2012-13, following up a Champions League title with a third-place finish in league play and knockout-round elimination in their title defense.
But that could just be the beginning.
According to Express, three of Chelsea's top players are all being eyed by top-flight European clubs, and Chelsea itself spent a full night bracing for a £100million raid on its stars. Per the report:
Mourinho is set to talk with them before a planned pre-season summit with his squad on July 8. He might have problems persuading all of them to stay.
That last part is of paramount importance. Mourinho might have problems persuading all of them to stay. And it's true: When the likes of Barcelona, Real Madrid and PSG come calling for multiple players, you can hardly expect to have 100 percent retention. At least one of them will get an offer they can't refuse.
Of the players mention, though, one stands out in particular as someone Chelsea can't afford to let walk. He stands out, above his supremely talented peers, as a man whose defection would cripple Chelsea's chances of repeating recent success next season.
And that man is Juan Mata.
Let me be clear: This is not at all a slight against the other names mentioned (well, maybe Fernando Torres). They are all vital parts of what Chelsea do, and in the case of David Luiz, even hold the team's assistant captaincy. But neither Torrest nor Luiz plays the same, irreplaceable style as Juan Mata, and that makes them easier players to lose.
Let's start with Torres. His demise has been greatly exaggerated, true, but his form at Stamford Bridge has still left something to be desired. He hasn't been the player he was at Liverpool, but he has been a useful enough striker up top. Scoring 22 goals in one season, even with a potent attack around you and 64 appearances to your name, is no small feat at this level.
Still, the bodies Chelsea has waiting to replace him are impressive. Romelu Lukaku was also mentioned as a transfer target by Express, but should he opt to stay, that's one name right there. On loan at West Brom this past season, he scored 17 goals in 35 league games.
They also have an experienced player in Demba Ba (for now), who could benefit from increased playing time in Torres' absence. He only made 22 appearances last season, and for a rhythm player of Ba's ilk, that is not enough to cultivate his full potential.
Add that to the list of strikers Chelsea could move to acquire—guys with a fraction of Torres' price tag, who could probably thrive just as well in this system—and its clear they could cope with Torres' loss.
David Luiz is, perhaps, a bit less expendable, especially from a leadership standpoint. The curly haired Brazilian has been a stalwart on Chelsea's back line, aiding teammates with both his technical skill and power.
But again, a crowded cadre of center backs make Chelsea able to cope with Luiz's loss. Branislav Ivanovic, Gary Cahill and John Terry are still very much in blue, and very much capable of patrolling the field's middle sector. Would Chelsea prefer to keep Luiz back there? Definitely. But would paying him be worth costing them Juan Mata? Absolutely not.
Which brings us, finally, to that man, Juan Mata, the player Chelsea can least afford to lose. Why, exactly? Because he's a unique entity to their team—a player who thrives at setting up others just as much as himself.
Torres and Luiz can both have their contributions imitated. For Mata, that is impossible. Nobody else on the squad is capable of passing like him, of creating like him or of seeing the field quite like he can. And that's something this attack can not afford to lose.
Which player can Chelsea least afford to lose this summer?
He accomplished an impressive (and rare) statistical feat in 2012-13, scoring 20 goals and racking up 35 assists in 64 appearances with the club. It was by far the finest year of Mata's career, a career that is finally starting to see him get Starting 11 time in meaningful matches with the Spanish National Team.
Quite simply, he's becoming one of the 20 best players on the planet.
With guys like Eden Hazard and Oscar on the flanks, Chelsea needs a pass-first player orchestrating things from the middle. It needs a guy who can see the field like Xavi, Mata's countryman, and put great scorers in position to score. Eden Hazard may want to score 60 goals in a season, which is great—but without Mata in the lineup, it's also (even more) impossible than it sounds.
Chelsea needs to keep up with Manchester United on the scoresheet next season. And if Barcelona or Real Madrid poaches Juan Mata from them, that would quite simply become impossible.
This attack would start to look like a mess.