The Napoli coach is fed up with the criticism of president Aurelio de Laurentiis and is ready to walk away at the end of this season.
Sarri snapped back at De Laurentiis publicly last week after his players were criticised by the president following defeat at Champions League opponents Real Madrid.
However, the rift runs deeper, says Gazzetta dello Sport, with Sarri threatening to quit on the spot after their recent draw with Palermo.
De Laurentiis confronted Sarri over his team selection and the coach blew up, snapping back before making the threat to quit. Sports director Cristiano Guintoli also was willing to walk.
Tensions have since eased, but Sarri is expected to quit once this season's commitments are over.