Manchester City's doctor has admitted the £35,000 fine for breaching Football Association anti-doping rules earlier this year has left a stigma over the club.The Premier League side were charged with breaking the FA's 'whereabouts' rules in January and a three-man panel fined the club in February.Clubs must provide the FA with information about training sessions and players' addresses so doping control officers can find them for no-notice tests.If clubs fail to provide this information - or testers are unable to find the players - three times in a rolling 12-month period, they are deemed to have breached the rule.City received three strikes in the space of five months in 2016, with the final breach coming three weeks after the FA sent a written warning.Speaking at the Soccerex Global Convention in Manchester as part of a debate on whether football has a doping problem, Dr Matthew Brown said the whereabouts system was "difficult" to manage for team sports and described the breaches as "admin errors".But Brown also took responsibility for the mistakes and said City, like most other Premier League sides, were in the process of creating a "whereabouts administrator" role to avoid any further issues."Years ago, it was up to the players but what was happening was the players would forget to (update their online whereabouts form) and the players would get sanctions," Dr Brown said."And if you get enough sanctions then that means a ban. Obviously, (the players) are assets for the club, so we don't want that to happen."(But) the key thing is the number of players involved. We're not just talking 25 first-team players - we're talking about the reserves, all the way down to the under-18s."And we need to update the FA if an under-18 player happens to go and train with the first team that day. I f we don't update that within a certain time-frame that morning, then that is potentially a strike."We're obviously not happy (about the sanction) as a club because it does bring our badge into disrepute but these have been admin errors and there have been no specific anti-doping offences."Dr Brown added that the clubs were working with the FA, UEFA and anti-doping authorities to make the online system easier to use, and most clubs typically made their players available for testing for an hour each morning during training.City's three strikes in 2016 came when manager Pep Guardiola failed to inform the FA of an extra training session in July, a first-team player missed a test in September because he had not updated his address and six reserve players missed tests in December because they had been given the day off at late notice.City were not the only club to fall foul of the FA's whereabouts rules last season, with Bournemouth and Fleetwood also sanctioned. The Premier League pair were fined the maximum amount allowed, £35,000, while Fleetwood had to pay £4,000.The size of those fines was criticised by several anti-doping experts and athletes from other sports, who pointed out that the penalty for missing three tests in a year for an individual athlete would most likely be a two-year ban and £35,000 was not a big enough deterrent for clubs earning at least £100million in broadcast rights alone.The FA has said it is reviewing the amount it can fine clubs and it is widely expected to increase those penalties.