Sunderland have been suffering with a lack of goalkeeping options for much of the campaign so far.
Villa are hoping to tie down Sam Johnstone on a permanent deal when his loan move from Manchester United expires.
The claret and blues also have Jed Steer in reserve, which means Bunn could be deemed expendable.
Sunderland should now keep a keen eye on the 33-year-old, as he could finally solve their goalkeeping issues.
Sunderland will need a new stopper in six months’ time, of that there is no doubt.
The Black Cats have Robbin Ruiter and Jason Steele as their current options in net, and neither of the pair have looked up to scratch.
Sunderland did bring in Lee Camp in January, but he is only at the Stadium of Light on a loan deal, and can only be seen as a short-term solution.
Bunn, though, could finally give Sunderland some solidity to build around in net.
The London-born stopper may have fallen out of contention at Villa, but he has previously proven to be a very reliable goalkeeper at Championship level.
And with Villa unlikely to stand in his way, Sunderland should already be considering making a move for the experienced custodian when the transfer window re-opens.