Both sides are ready to close the deal, and Napoli director Cristiano Giuntoli met with Ndombele’s representatives in Paris to discuss personal terms.
Ndombele joined Spurs from Olympique Lyon in the summer of 2019 for a club-record £65 million fee, but he has since failed to live up to expectations.
He came in with a reputation as a box-to-box midfielder adept at ball recoveries, ball progression and progressive carries into the final third.
However, he failed to deliver the consistency and quality promised by his fee.
The 25-year-old found playing opportunities hard to come by when Rodrigo Bentancur joined the club in January, and the summer signing of Yves Bissouma has further confirmed his status as a fringe player.
After struggling to impress under Jose Mourinho and Antonio Conte, the France international returned to Lyon on loan for the second half of the last campaign.
Since returning to north London last month, he is one of four players who have reportedly been banished from first-team training, along with Giovani Lo Celso, Sergio Reguilon and Harry Winks.
Lo Celso has agreed to return to Villarreal on a simple loan deal, and Ndombele is the next through the exit door as Spurs boss Conte continues his summer clearout.
Ndombele had previously hinted he would like to stay at the Tottenham Hotspur Stadium as he thinks it would be possible to be happy at the club, but a move away is now close to being finalised.
The Frenchman has featured 91 times for Spurs in the last three seasons, contributing ten goals and nine assists. He has also made seven senior appearances for his national team.
Villarreal and Newcastle United were also interested in signing the Frenchman but were beaten to the punch by Napoli.
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