The 23-year-old Jamaica international is valued at around £30million and has previously been tracked by both Arsenal and Manchester United.
Bailey enjoyed his best season for Leverkusen last year, scoring 15 goals and creating 11 more in 40 appearances.
Capable of playing on either flank, he is an attractive proposition for Villa, who are focused on increasing their attacking options this summer and will be without Trezeguet for the first half of the season, as the Egyptian recovers from a serious knee injury.
Villa’s primary targets have been UK-based players with Premier League experience and Burnley’s Dwight McNeil has been closely monitored.
But sporting director Johan Lange and his recruitment team have also been looking at Europe’s big five leagues and Bailey, who has spent the past four years in the Bundesliga, is viewed as an attainable target.
The former Genk ace is currently away in the USA representing his country in the Gold Cup.
Ambitious Villa have already broken their transfer record this window with the signing of playmaker Emi Buendia from Norwich for an initial £33million.
But veteran wideman Ashley Young is their only other addition to date, with two bids for Arsenal’s Emile Smith Rowe having been rejected.
Easing the creative burden on Jack Grealish remains the aim, though the skipper’s own future is still to be resolved amid serious interest from Premier League champions Manchester City. Villa are still hopeful of getting the 25-year-old to sign a new contract.
Adding a goalkeeper is also among the club’s requirements following the departures of Tom Heaton and Lovre Kalinic. Former Fulham goalkeeper Marcus Bettinelli has been mooted as a possible target.
Smith, meanwhile, is currently away from Bodymoor Heath and isolating with his family. The Villa head coach was also absent from last night’s friendly at Walsall.