Manchester City have until 4pm on Friday to respond to a Football Association charge of breaching anti-doping rules.
Earlier this month, the FA charged City following an alleged third violation of rules concerning "club whereabouts" in the space of 12 months.
No specific details were given but PA Sport reported that the charge is one of misconduct relating to the club in general rather than any particular individuals.
Clubs are required to keep the FA informed of the location of their players in order to facilitate drug-testing.
This would include providing the times of training sessions, home addresses of players or other addresses where the team may stay overnight.
Rules state a breach occurs "if the information contained in such reports is either initially inaccurate or has not been updated by the club as necessary to ensure it remains accurate."
A "three-strike" policy is operated, meaning a charge is only triggered after three infringements in the space of a rolling one-year period.
The system mirrors that of one operated for athletes by the World Anti-Doping Agency but is not directly connected to that body, which does not have provision for team sports. It therefore concerns FA rules only.
It is thought City are most likely to be fined if found guilty. The club were initially given until Jan. 19 to respond but requested additional time to consider the matter.
They have so far declined to comment.