The Professional Footballers' Association, the trade union for players in England and Wales, is facing a statutory inquiry into serious concerns about how the charity is run.
The UK government's Charity Commission describes the inquiry as the "most serious intervention" it can make, and will focus on the management of the players' union charity by its trustees, who include PFA chief executive Gordon Taylor.
The inquiry will focus on the charity's relationship and transactions with other bodies and whether they are in the best interests of the charity, and whether its activities have been exclusively charitable and for the public benefit.
The Commission's head of investigations, monitoring and enforcement Stephen Grenfell said: "The public rightly expect charities to operate to the highest standards -- across all they do.
"Serious concerns have been raised about the way the Professional Footballers' Association charity is run. We will now examine what has happened at the charity through a full statutory inquiry and ensure, where necessary, action is taken."