Napoli will therefore need a new manager to defend their Serie A title next season.
Spalletti signed a three-year contract when he moved to the Diego Maradona Stadium in the summer of 2021.
He led Napoli to a third place finish in his first full season in charge before ending the club's 33-year wait for a Scudetto title this term.
Napoli also reached the quarterfinals of the Champions League for the first time in their history under Spalletti.
Napoli lost some key players at the start of the season as the likes of Dries Mertens, Kalidou Koulibaly and Lorenzo Insigne departed but some shrewd signings in the shape of Khvicha Kvaratskhelia and Kim Min-Jae proved more than capable of filling the void.
“Spalletti is a free man," De Laurentiis told Che Tempo Che Fa on Rai 3.
“When someone comes to you and says that he has done all he can and an era of his life has concluded… He told me that he would prefer to have a sabbatical year. What do you do then? Do you oppose it?
“He gave me a great deal, I thank him. Now it is only right that he continues to do what he loves."
“In June last year I held a press conference. We had got rid of many players who were considered important, but for me had finished their time at Napoli.
“The journalists asked me, considering all the farewells, what I was thinking of aiming for this season and I said I thought we could win the Scudetto. There was total shock, even Spalletti looked at me in shock, because he didn't know who we had bought.
“He has been a great coach to these lads. Coaches are divided into those who want to control the transfer market and those who get down to coaching. We gave him some extraordinary material to work with and he helped them improve."
Spalletti's last game in charge of Napoli will be against Sampdoria on Sunday.