Previously, the FA had only been able to take retrospective action against a player where none of the match officials had seen an incident whatsoever, or where an incident was judged to be "truly exceptional". The earlier rules permitted reviews of and disciplinary decisions against "off the ball" incidents, for example, which were not seen by match officials. However, they did not capture a foul which the referee may have been unable to see but which his assistants had some, albeit limited, sight of.
The rule change follows concerns regarding a tackle by Wigan Athletic's Callum McManaman on Newcastle United's Massadio Haidara in March 2013. This was widely considered to be a dangerous challenge which ordinarily would almost certainly have resulted in a red card (and suspension) being awarded to Mr McManaman. The referee did not see the incident. However, because one of his assistants did have limited sight of it, albeit without being in a position to assess "the full extent of the challenge", the option of retrospective action was not open to the FA.
Under the new rules on "not seen incidents", the FA would not have been prevented from taking retrospective action against Mr McManaman on the basis that an assistant match official had had some, limited sight of the incident. If the match official considered that, despite seeing a challenge, they could not fully assess the gravity of it, then the option of retrospective action would then be open to the FA.
The issue of retrospective action remains a controversial topic in football governance. Much like criticisms regarding goal line technology (also to be introduced in the 2013 - 14 season), there is concern that this could result in the "re-refereeing" of matches by video. However, even under the new Rules, retrospective action will only likely be pursued where a sufficiently serious incident has occurred, and one which would ordinarily have resulted in further disciplinary action (typically a suspension) being taken as a result of the incident in issue alone. Such incidents include violent conduct, serious foul play, or using offensive or insulting language. Even with the benefit of video footage and retrospective decision making, FIFA's Law 5 remains absolute: "Each match is controlled by a referee who has full authority to enforce the Laws of the Game in connection with the match to which he has been appointed."