Even though Postecoglou made nine substitutions for Tottenham’s Carabao Cup loss to Fulham in a penalty shootout, the 26-year-old has not appeared in any of the team’s games this season.
Ndombele, who spent the previous two seasons for six months at Lyon and the previous season for the Italian champions Napoli, is currently considering a season-long loan transfer to Genoa.
Spurs are battling to recuperate even a small portion of the £63 million they spent on their disappointing club-record acquisition from Lyon.
The seven-time France international is still under contract for two more years at a salary of £120,000 a week.
Postecoglou announced on Tuesday night that he intends to reduce the number of players in his squad, with up to seven Spurs players potentially available for departure.
He said, “We need to trim the squad and get it to a more manageable state and see what’s available for us to bring in players to strengthen a couple of players we may need.”