The 33-year-old midfielder has not not played for Villa since March 2012 after being diagnosed with acute leukemia.
The Bulgarian started his career at PFC Montana in his homeland before earning a move to CSKA Sofia, where he won a league championship and two cup competitions. A two-and-a-half year stay in the Bulgarian capital ended when Celtic paid 2.8 million pounds for his services in 1999.
Success at Celtic Park followed as Petrov won four league titles along with three Scottish Cups during his seven-year stay at the Glasgow club before he moved to Aston Villa in the summer of 2006.
Petrov was part of a successful Aston Villa team that reached a Capital One Cup final in 2009, losing 2-1 to Manchester United and finished sixth in the Premier League in 2008. Fans at Villa Park have been holding a minute's applause during the 19th minute of every home game in honor of Petrov, who wore No. 19 for the club, and his cancer is now in remission.
Petrov released the following statement on Thursday:
"I've never been a person for making grand statements. I've only ever got on with my job, while remaining grateful to have great teammates, great people around me and, most of all, a fantastic family. They have been powerful pillars of support when I have needed them most over the past year.
"To my wife, Paulina, and my sons, Kristiyan and Stiliyan, I love you very much and I will always for your constant love and support. Also to my mum and dad, my brother and Paulina's mum and the people who have been closest to me throughout this time - you know who you are and I love you all. Each and every day I thank God for giving me the opportunity to still be with my family.
"Football has been the other great love of my life, so it is with a heavy heart that I am announcing my retirement from the game. The emotions are overwhelming really, but the continued support of family, friends and the great people I have come to know will make it easier for me to move on from the only life I've ever known.
"That I am ready to embrace new challenges will make this process much easier. Since being diagnosed with acute leukemia in March 2012, I have come to understand and appreciate the way in which this disease impacts the lives of so many people. I can help and I want to help and, in setting up a foundation to help address the issues involved when people are diagnosed with this illness, I hope to make a difference. This will be my new challenge, one I will face with all the enthusiasm, energy and drive with which I have faced every single challenge.
"I remember when I was a young player at CSKA Sofia and the good life was all I was interested in. Celtic came in for me and I moved to Glasgow, to another country, to a new world. I didn't speak the language and I thought it would never happen for me. I knew nobody.
"Fortunately, I met people who helped me to turn my life around. I came to know great teammates who showed me the proper way, the way I had to be if I was going to be a serious professional and compete at a high level. I came to appreciate so much the opportunity to work with that level of professional people because it made me something like them. At Celtic Football Club and at Aston Villa Football Club I was privileged to live a life competing at a high level and playing the game I love, supported by the most passionate fans.
"Then something crazy happened, something I thought was just a cold but turned out to be something more serious, something life-changing. I played 90 minutes for Villa against Arsenal at The Emirates and I felt fatigued, not myself at all. But I thought it was nothing serious. The diagnosis by Dr. Richard Lovell was a complete shock.
"Around 7,600 people in the UK are diagnosed each year with leukemia and about 2,300 people with acute leukemia. Fortunately, I was able to make decisions very quickly and I started my treatment quickly. I needed to. My leukemia is now in remission and I have finished my high intensity treatment. From now on I'll be on the softer treatment, which is two years on tablets. I feel lucky. Not everyone is as lucky as I have been.
"For this I need to thank Professor David Linch at University College London Hospital, his PA Teresa Macdonald and all of the nurses and staff at that wonderful institution. Thank you also to Professor Charlie Craddock, Sandeep Nagra and all of the nurses who have looked after me at University Hospital and Queen Elizabeth Hospital in Birmingham.
"For the life I've lived in football, I will always be incredibly grateful. For the opportunity this crazy thing that happened in my life has given me, I also feel grateful in a strange kind of way. This crazy thing, somehow, has touched people and I want to try to channel this in a positive way. This will be the greatest challenge of my life.
"I wish to thank the fans of Aston Villa and the Villa chairman, Randy Lerner, chief executive Paul Faulkner and manager Paul Lambert, also the fans of Celtic, the Bulgarian fans and fans of football all over the world who have helped me through the past year with their incredible displays of support and with their personal, moving messages.
"I would also like to thank all of the managers I have worked under and all of the team-mates I have played alongside. I loved playing football with all of you and you will always remain in my heart. Also to the agents who represented me, including my current agents Base Soccer. I am moving on and I am excited by this. There is a deep joy in my heart because of what you have shared with me, not only in this past year but over the years I have been in football. I felt privileged. I still do. I always will."