The departures at the end of their contracts come as the English Premier League club, which just avoided relegation this month, searches for a new manager after Alex McLeish was fired.
Heskey, who at 34 is the oldest of the players to leave, has been at Villa since being signed from Wigan in January 2009.
Guzan is ending his four-year stay at Villa after being frustrated at his lack of action, having made just nine appearances this season, mainly covering for the injured Shay Given.
Cuellar has been a versatile performer for Villa, operating at right back, left back and center back in five years at the central England club.
Aston Villa release Guzan, Heskey, Cuellar
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