Alderweireld's current deal with Spurs expires in 2019, and while the Premier League side have the option to extend that deal by a further year, triggering that option would enable clubs to sign the Belgian for just £25 million next year.
The Sun reports that Alderweireld has not signed a new deal with Mauricio Pochettino's side. And with a host of their top flight rivals chasing his signature - including Manchester United, Manchester City and Chelsea - The Sun suggests that Spurs may consider selling this month to ensure that they get a good price for the 28-year-old.
The Sun adds that Tottenham's players fear that Alderweireld's lack of game-time since his return from injury is a potential sign that he may be on his way out at the end of the season as it somewhat mirrors the kind of run Kyle Walker went through before his Manchester City move last year.
Should Tottenham sell this summer?
If Alderweireld makes it clear that he has no plans to extend his contract with Spurs, then that undoubtedly leaves Tottenham in a difficult position heading into the summer.
If clubs come calling with bids significantly higher than £25 million, then Tottenham should consider selling the former Southampton man as they will not be able to make that kind of money beyond next summer unless he extends his contract.
However, with Davinson Sanchez and Juan Foyth proving to be talented defenders who have extremely bright futures ahead of him, perhaps it may be worth gambling and keeping Alderweireld beyond this summer if they feel that with the players they already have and an additional £25 million in the kitty, they will end up in a better place letting him leave in 2019 than if they decided to sell him for a larger amount this summer.