The Belgium international midfielder has been deemed surplus to requirements by boss Unai Emery and was not part of the travelling squad for Villa’s recent pre-season tour of the USA.
Dendoncker spent last season on loan back in his homeland with Anderlecht but they declined to trigger an option to buy.
It meant the 30-year-old returned to Villa for the second pre-season running having failed to secure a permanent move away, with Napoli having also opted against triggering a buy option following a disappointing loan spell in the second half of the 2023-24 campaign.
Finding a new club for Dendoncker, who has one year left on the deal he signed after joining from Wolves for £13million in 2022, has so far proven tricky this summer.
Another loan departure is still the most likely scenario yet an early termination of his contract, while still seen as a last resort at this stage, cannot be ruled out.
Villa also want to move left-back Alex Moreno off the books with Girona among several suitors in Spain.
Moreno, who became Emery’s first Villa signing when he joined from Real Betis for £13m in January 2023, spent the whole of last season on loan with Nottingham Forest.