Villa have made an £18million bid for the 26-year-old England international.
Bent has asked to quit the Black Cats, who he joined from Tottenham 18 months ago in a £10million deal.
Sunderland have yet to respond to Bent’s request to leave the club in the January transfer window.
The Black Cats have also yet to decide over whether to accept Villa’s £18million bid for the striker.
