The Republic of Ireland defender was released by Villa two years ago.
The Irishman has been in good form at Portsmouth this season.
The Irishman had been playing away from Aston Villa last season, on loan at Doncaster Rovers.
A look at what the future holds for the club's loanees with a new boss now in place.
Aston Villa's Enda Stevens is expecting to leave the club soon.
With his contract expiring next summer, out-of-favour left-back Enda Stevens admits that his Aston Villa career is over.
Aston Villa have some big decisions to make about eight of their current players, but the stars have a few decisions of their own.
All the latest summer transfer news from League One...
Enda Stevens, Nathan Delfouneso, Samir Carruthers, Graham Burke and Darren Bent all feature.
Aston Villa's Enda Stevens impressed at the weekend when he kept Manchester United's Antonio Valencia quiet.