The 29-year-old was suspended by Villa after allegedly going on an alcohol-fuelled laughing-gas binge on the day their relegation was confirmed two weeks ago.
"I do not deserve to carry out such a role anymore," Agbonlahor said on Instagram.
"This role was a huge honour to me and it hurts to have lost it."
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Villa imposed a "substantial" fine on Agbonlahor and reminded him of his responsibilities to the club.
Agbonlahor was also photographed apparently smoking a shisha pipe while partying at a Dubai night club three weeks ago but Villa decided not to punish him for that incident.
Agbonlahor, who has been at the midlands club for over 20 years and has won three England caps, apologised for his behaviour.
"I am asking Aston Villa fans for forgiveness as I'm hurting as well despite reports and photos in the press making out otherwise," he said.
"I agree my performances this season have not been good enough but I will be working hard to make things right! Up The Villa, Villa Till I Die!"
(Reporting by Ed Osmond, editing by Pritha Sarkar)
