According to the Times, Alderweireld is demanding a weekly wage of £150,000, around £40,000 more than Spurs - a club with a notoriously rigid wage structure - are willing to offer.
With no compromise likely and with Alderweireld soon to turn 29 years of age, it is said the north London club believe a sale would instead now be in their best interest. The money raised and saved could then be used to reinvest in the squad.
Alderweireld's contract is currently due to expire in 2019, but has a 12 month extension clause than, when triggered, also activates a £25m release clause. Therefore Spurs are well aware that this summer is their best and last opportunity to command a big fee of around double that.
The summer of arrivals of Davinson Sanchez, 21, and Juan Foyth, 20, are likely to be a factor in Spurs willing to let Alderweireld, who is only recently back from a lengthy injury layoff, leave.
This latest update is likely to put various suitors on alert. Manchester United were recently reported to be keeping an eye on the player, while Chelsea are another top Premier League side in the market for a centre-back - the Blues are currently linked with Jamaal Lascelles.
Real Madrid have also been linked with Alderweireld in the past, while Manchester City were linked before completing the £57m signing of Aymeric Laporte in January.
Alderweireld, who has 68 senior caps for Belgium, first arrived in England when he joined Southampton on loan from Atletico Madrid in 2014. He later joined Spurs for £11m and since played over 100 games for the club.