The super-agent, who has played a significant role in the success of Wolves as an adviser to the Molineux board, is understood to have been drafted in by Nassef Sawiris and Wes Edens.
Mendes is thought to be working on a number of potential deals, though it is believed the final say on signings will still rest with manager Steve Bruce.
Atletico Madrid goalkeeper Andre Moreira, a Mendes client, has already been lined-up on a season-long loan. The 22-year-old is not thought to have been scouted by Villa before arriving at the club late last week.
Bruce, meanwhile, is keen to pursue a loan move for Liverpool’s teenage star Ben Woodburn, while Robert Snodgrass could also return should he be deemed surplus to requirements at parent club West Ham.
Turning to Mendes still marks a change of direction for Villa and the Express & Star understands Sawiris and Edens hope to develop relationships with a handful of other top agents in order to secure premium talent.
Loan deals remain the most likely scenario for Villa, who still need to find around £40million over the course of this transfer window and the next in order to comply with FFP rules.
It has also emerged the club was operating under a ‘soft’ transfer embargo before Sawiris and Edens invested £35million to ease a cash crisis.
The duo now control 55 per cent of the club, with former owner Tony Xia still holding a 45 per cent stake.
An EFL spokesman said: “The EFL has completed its review of the change of control application made by Aston Villa Football Club.
"The club and its shareholders are required to comply with a number of financial reporting requirements moving forwards.
“The EFL can further confirm that the club is not subject to a registration embargo.”