Complex sentence: The fact that a playoff would be required between Collingwood and South Melbourne was known after Round 19; both Collingwood and South Melbourne were scheduled with a bye in Round 20, and third-placed Essendon was six premiership points adrift with no chance of finishing first.
Split into simpler sentences: The fact that a playoff would be required between Collingwood and South Melbourne became clear after Round 19. Both Collingwood and South Melbourne had a bye in Round 20, with third-placed Essendon six premiership points adrift, leaving them with no chance of tying for or finishing first.