The Argentine playmaker has spent the last year and a half on loan at Villarreal, who have shown no desire to make his stay permanent.
Former Villarreal boss Unai Emery is a keen admirer of Lo Celso, having facilitated his loan move to Estadio de la Ceramica.
But his departure has reduced the chances of Spurs man joining the La Liga club permanently.
Lo Celso has been linked with a move to Aston Villa to reunite with the Spanish manager, but the club currently have other priorities in the transfer market.
The Polish midfielder has one year left on his contract with Napoli and has refused to sign a new deal amid reports that the club tried to force him to take a pay cut.
With the possibility of an extended contract out of the question, Lazio are trying to use the player’s situation as a bargaining chip to land his signature on a cut-price deal.
However, Napoli chief Aurelio De Laurentiis is famous for being a tough negotiator and has already rejected an opening bid from Lazio, with the Partenopei holding out for a fee closer to €30 million.
While negotiations between both clubs rumble on, Napoli have opened talks of their own, with the club keen to sign Lo Celso on loan with an option to buy.
However, Tottenham are determined to get the former Paris Saint-Germain man off their books permanently and are favouring an outright sale.
Both clubs could settle for a loan deal with a buy obligation, but Lo Celso will have to take a pay cut to facilitate the move, as his current earnings are more than what Napoli are prepared to offer.