Aston Villa midfielder Stiliyan Petrov has been diagnosed with acute leukaemia, according to the club's website.
Petrov was taken for tests following Aston Villa's game with Arsenal on Saturday, after he began suffering from a fever. Haematology reports confirmed the diagnosis of the illness today.
We expect to learn more about Stiliyan's situation in due course and we have moved quickly to support him and his family, read the statement by Aston Villa.
During this time we ask that Stiliyan's privacy is placed ahead of all inquiries and trust that we will share information as we receive it.
Stiliyan is cherished by many and he will get from Villa every ounce of love and support that we have to help bring this to a positive conclusion.
Petrov, 32, has been a virtual-ever present for the Midlands side this season making 26 starts and one substitute appearance. He played the full 90 minutes in Villa's 3-0 loss to Arsenal at the weekend.
Petrov moved to the former European Champions in 2006, following the then-manager Martin O'Neil, with whom he had enjoyed a successful spell under at Celtic.
The Bulgarian international signed for the Glasgow giants in 1999, where he went on to win four league titles and help the team to the final of the UEFA Cup in 2003 where they suffered an extra-time loss to Porto.
Petrov has made 105 appearances for his country and also captained his nation, after beginning his career with CSKA Sofia.