With Napoli and Chelsea in the final stages of negotiating a price over compensation for Sarri's move to London, here's what some of the game's biggest names have said about the 59 year-old master coach just in the last year:
PEP GUARDIOLA (Manchester City manager): "I have no doubt that Sarri is among the strongest ever, sometimes we judge for what we win. What he did with Napoli, the shape of his football is like toast in the sun.
"He did very well, seeing Napoli play on the sofa for someone watching football is a show. If he comes to England it will be a pleasure."
PAOLO DI CANIO (Ex-Italy international): "He's a phenomenon. He does the same things as (Pep) Guardiola at (Manchester) City, pressing high, regaining, high defensive line, possession, but with less powerful players.
"He has good players but Allan is not (Kevin) De Bruyne or (David) Silva. And Jorginho is not Fernandinho etc."
AURELIO DE LAURENTIIS (Napoli president): "I have always been very polite to him, I have always supported him. But at some point if you have a contract with me for another two years and begin to publicly express doubts, doubts such as 'I do not know if I stay', 'I do not know if the club will keep it's best', 'in life better to finish when the stories are beautiful', you send clear signs of intolerance and distrust, disregarding your contractual obligations and giving me possible damage.
"I'm a very reasonable guy, so if someone comes to treat ... I'm not a vindictive guy, Sarri will always have my thanks. Maurizio never replied to me about a possible future in Naples. If you close the door in my face, I politely restrain myself not to disturb your work, but up to a certain point, beyond which I have the right, indeed the duty to safeguard this club by starting to look around. When he said 'I want to enrich myself with the next renewal'. I considered it an offense."
JUAN SEBASTIAN VERON (Estudiantes chairman): "They played by heart, I would have liked to be in that team. Better: I would have liked that he had trained my great Parma, with Chiesa and Crespo in front, me, Dino Baggio and Boghossian in the middle, Cannavaro, Sensini and Thuram in defense, Buffon in goal. How we would have enjoyed it!"
FABRIZIO CORSI (Empoli president): "Sarri? I do not know what will happen in his future. I read the newspapers and I understand that there is a certain silence around this situation. He deserves a big club, he is a fantastic coach.
"Have I heard from him? Absolutely not, not even someone from his staff. Maurizio made a professional choice, but humanly the separation with Napoli has hurt him."
"He wrote: 'but how well do they play? Nobody does it this way in Europe'.
"Yet, if you think about it, Napoli does not even have a top-player on paper. I myself had a team with great strength, which is absent among the Neapolitans. They have to play on the synchronisms, on the freshness, on the enthusiasm: as soon as they fall, the limits emerge."
CORRADO FERLAINO (Ex-Napoli president): "Sarri is for Napoli what in my day was Diego Maradona. And for this reason I am also very worried, because Sarri could leave at the end of the season, attracted by big clubs."
IVAN STRINIC (Sampdoria fullback): "I did not go to Napoli to sit on the bench and look at my bank account. My chance, Sarri has given me a chance, every now and then but he has never given me the continuity of those 6-7-8 games in a row, which are necessary to prove something.
"Yet every time I played the criticisms and the judgments were positive, but Sarri is like that, even from the human point of view he is very cold."
ANTONIO CASSANO (Ex-Sampdoria striker): "Sarri always plays the usual ones. I like coaches like (Max) Allegri who leave room for inventiveness, that of Sarri is a game where everyone knows what they have to do.
"Having a coach that makes you do three hours of tactics a day is tough. "
LUCIANO MOGGI (Ex-Juventus director general): "What does Sarri know about winning the European Super Cup Final? Has he ever been there? This year he was eliminated from the Coppa Italia, the European Cup, the UEFA Cup and soon it could also be second in the league.
"Napoli revels, it is a mirror and looking in the mirror as they play well. Putting players on the field when they see themselves playing well is different than putting players who want to win.
"As long as Sarri stays in Naples, Napoli will not win anything, because good players do not go there knowing that there are those who will always be selected first."