Simon Grayson's side are hopeful of completing a deal before Friday night's visit of Derby County in the Championship's season opener.
Grayson signed McCormack when in charge at Leeds United and is hoping that the striker can help to replace the goals lost by Jermain Defoe's move to Bournemouth.
Prior to his move to Villa, McCormack was considered one of the most dangerous strikers outside of the Premier League, though a disappointing season under Steve Bruce has seen his stock drop considerably.
The former Fulham man scored just three times in 22 appearances for Villa last season and ended the campaign on loan with Nottingham Forest.
The 30-year-old has hardly appeared for Villa during pre-season though one sticking point of the deal could come in the form of the player's wages.
McCormack is believed to earn £45,000 per week at Villa and with Sunderland looking to cut their cloth accordingly following their relegation, there are doubts as to how much they would be prepared to contribute.