So if a Green Lantern does show up in Justice League, how might it happen?
Assuming that this member is someone unknown rather than notable, maybe this particular Lantern comes across Steppenwolf, one of Darkseid’s chief minions from Apokolips.
This sequence may not be as action-packed, but it would lay groundwork for the DCEU’s future.
The Green Lantern Corps are essentially the intergalactic “beat cops” of the DC universe, so it’s plausible that one of its members comes across Steppenwolf and his Parademon army at the beginning of the story while on patrol, and they’re subsequently eliminated.