Not much is known about DC's vision for their Green Lantern franchise, other that it exists and will likely be introduced in Justice League, though a recent post on social media might be the first clue.
The post comes from actor Andre Gordon (Modern Family, Miraculous: Tales of Ladybug and Cat Noir), who shared a picture of John Stewart's Green Lantern with the caption "andregordonofficialThe pieces are coming together and it feels good! #johnstewart #greenlantern #greenlanterncorps #justiceleague #4HorsemenFilms"
This fits in line with previous rumors that point towards multiple Green Lanterns from sector 2814 being in the film universe and eventually in the Green Lantern Corps film. This is likely to consist of John Stewart, Hal, and possibly either Guy Gardner and Kyle Raynor. If this turns out to be true, that means that John Stewart could very well be the main Green Lantern of the Justice League, though most are still betting that it will be Hal Jordan.
Fueled by his restored faith in humanity and inspired by Superman's selfless act, Bruce Wayne enlists the help of his newfound ally, Diana Prince, to face an even greater enemy. Together, Batman and Wonder Woman work quickly to find and recruit a team of metahumans to stand against this newly awakened threat. But despite the formation of this unprecedented league of heroes—Batman, Wonder Woman, Aquaman, Cyborg and The Flash—it may already be too late to save the planet from an assault of catastrophic proportions.
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The Green Lantern Corps movie will be released in 2020. Justice League will be released in 2017.