In Mighty Morphin’ Power Rangers, Rita gave Tommy the Green Ranger powers and brainwashed him into serving her until the five main Rangers broke the witch’s control over him.
While Rita is the first Green Ranger in the Power Rangers cinematic world, if the movie is staying faithful to its TV predecessor, then it stands to reason that in the next movie, we’ll be introduced to Tommy Oliver, the original Green Ranger.
From there, Tommy joined as the sixth member of the superhero team, and as time wore on and his Ranger powers changed, he eventually became the most popular and famous Ranger of all.
So yeah, expect him to become a major player at this new series of movies progresses.