In 2019, he signed a contract extension with Spurs to keep him at the club until 2023.
Voetbal 24 says Alderweireld is wanted by Belgian champions Brugge.
The speculation comes as he was left out of Spurs' squad for a second successive game on Sunday.
Alderweireld has played 27 times for the Lilywhites so far this season, 18 of which have come in the Premier League.
However, he is fighting with a number of players for a first team place.