Manchester City have been fined £35,000 ($44,000, 41,000 euros) after accepting they breached Football Association rules on anti-doping.
A statement issued by the FA, English football's governing body, on Thursday said City had failed to ensure their "club whereabouts" information was accurate.
The fine was imposed following an independent regulatory commission hearing.
Charges against City were levelled in January following an alleged third violation of 'whereabouts' rules in the last 12 months.
Clubs must provide accurate details of training sessions and player whereabouts so they are available for drug testing at all times.
No specific details of the three incidents involved have been made public, but it is understood City face a general misconduct charge rather than one relating to particular individuals.
The FA conducts drug testing post-match, at training sessions and at players' home addresses.
Players can be selected for a drug test in either a random or a targeted basis.
In the last FA figures published, in 2014, there were nine violations from a total of 152,286 samples.
The charge facing City was purely an FA matter as the World Anti-Doping Agency and UK Anti-Doping do not have the jurisdiction to cover violations of drug rules by sports teams.
Thursday's statement from the FA read: "Following an independent regulatory commission hearing, Manchester City have been fined £35,000 and warned as to their future conduct after admitting a breach of the FA's rules on anti-doping. "City were charged with failing to ensure their 'club whereabouts' information was accurate, contrary to Regulation 14(d)."
City subsequently told the Press Association, Britain's national news agency, they would not be commenting on the matter.