Last season, The FA introduced the fourth substitute in extra time from the quarter final stage of the competition, following a study from the International Football Association Board (IFAB) to analyse the impact an additional substitute in extra-time would have on a match and its outcome.
In the event Hereford or Slough Town need a replay which goes to extra-time in their second round games versus Fleetwood Town and Rochdale respectively, then they may use one additional player from the nominated seven substitutes during the period of extra-time.
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