Carlisle has been working as a commentator for ITV since retiring in May 2013
Former Professional Footballers' Association chairman Clarke Carlisle is in hospital after being involved in a serious road accident on Monday.
The ex-Burnley defender, 35, was airlifted to Leeds General Infirmary.
The cause of the accident is unknown, although the BBC understands his injuries are not life threatening.
Equality campaign body Kick It Out, for which he is an ambassador, tweeted: "The thoughts and prayers of everyone here are with Clarke and his family."
The tweet added: "Stay strong our dear friend - keep on fighting."
The Football Association tweeted: "The thoughts and prayers of all at the FA are with Clarke Carlisle and his family at this sad time."
The defender celebrates winning promotion to the Premier League with Burnley in 2009
Centre-back Carlisle made more than 500 appearances during a playing career spanning 16 years at nine clubs, including Leeds and QPR,
He retired from professional football in 2013 after his last club, Northampton, were beaten by Bradford in the League Two play-off final, before working as a TV pundit.
Burnley FC tweeted: "The thoughts of all at Burnley Football Club are with Clarke Carlisle and his family."