Premier League rules:
The Board shall have power at any time to change the date upon which a League Match is to be played. Before exercising such power the Board will consult with and take into account any representations made by the Clubs participating in the League Match in question and any other Club or Clubs which may be affected thereby.
A Club engaged in any match played in a UEFA competition on a Thursday evening and a League Match on the following Saturday may rearrange the League Match to the following Sunday provided that:
L.7.1. it gives notice to that effect to the Secretary and to its League Match opposing Club within 72 hours of the date of the UEFA match being fixed (or, if the period of 72 hours expires on a day which is not a Working Day, by close of business on the first Working Day thereafter);
L.7.2. there is no police objection;
L.7.3. the rearrangement of the League Match does not result in the opposing Club having to play another League Match, F.A. Cup match or UEFA match within 2 days of the rearranged League Match being played.
A Club may apply to the Board to rearrange a Saturday fixture so that it is played on the preceding Friday or the following Sunday and in considering whether to exercise its power to do so the Board shall have regard also to:
L.8.1. theprinciplethatsuchapplicationsshallnotnormallybegrantedinrespect of more than 2 League Matches in any one week;
L.8.2. the effect any such rearrangements would have on published football pool coupons.
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Good to see that they take pools coupons into account but couldn't give a shit about the fans.
Saying that, FA Cup dates are published at the start of the season so we are always aware of such postponements being likely.