The 25-year-old struggled to make much of an impact in his first season at White Hart Lane following an £7 million move from FC Twente last summer, and Sunderland are now hoping to land Chadli on loan for the season.
The arrival of the Belgian would give Gus Poyet more options out wide, and Chadli would likely see regular first-team action if he were to make the switch.
Spurs were believed to be trying to use the midfielder as part of any approach for PSV Eindhoven's Memphis Depay, but Chadli has insisted that he wants to remain at Spurs and fight for his place under Mauricio Pochettino.
Interest from Sunderland may make him think twice as the opportunity to see regular action in the Premier League is what any player wants, but Chadli will want to improve on his first campaign in England with the Lilywhites, as several other signings from last summer will want to do.
Erik Lamela, Roberto Soldado, Vlad Chiriches, Etienne Capoue and Chadli will be looking to make an impression at Tottenham this year after fairly difficult debut campaign's in English football.
Poyet has reportedly inquired about taking the former FC Twente star on loan, though Tottenham would prefer to listen to firm offers for the Belgian.
Tottenham have Andros Townsend, Aaron Lennon and Lamela as well as Chadli as options on the wings, and Chadli would only be allowed to leave if another wide-man was brought in.
The north London club will hope that a deal can be reached with PSV for Depay, though that deal may affect Sunderland's chances of landing Chadli, as Pochettino will need depth in every position as Spurs will compete in four competitions once again this year.