Heskey had already indicated he would be leaving after the final home game of the campaign against Tottenham and he has not been offered a new contract.
Defender Carlos Cuellar has also parted company with Villa but the Spaniard is looking to remain in England. Number two keeper Brad Guzan is the third first-team squad member to be leaving Villa Park at the end of his contract.
Heskey, who joined Villa from Wigan during January 2009, has made it clear he wants to continue playing and has been linked with his first club, Leicester.
He has been dogged by an Achilles problem this season but returned to the side during the latter part of the campaign.
Cuellar moved from Rangers in an £7.8 million deal five years ago and became a versatile performer in operating at right-back, left-back and centre-back.