The winner of the Melbourne-Geelong clash will likely be given their choice of whether to play a Friday or Saturday night contest and their choice of venue outside of Victoria.
McLachlan confirmed on Friday there would be no finals in Victoria in the first two weeks.
If Melbourne chose the Friday night they would be playing their third six-day break in a row after a Monday Perth game in Round 22.
The minor premier is usually keen to play a Friday qualifying final off the pre-finals bye to maximise their chance of an eight-day break leading into the Grand Final.
But this year with a likely pre-Grand Final bye the minor premiers — likely Melbourne or Geelong — could play a Saturday final next week and still be guaranteed a 14-day break leading into a Grand Final.
The league will attempt to pair the 1 v 4 final in a timeslot close to the 5 v 8 match-up given the loser of 1 v 4 will play the winner of the 5 v 8 contest.