In a tweet on December 17, 2016, Rebels Reactions posted a photo of a Star Wars Rebels poster, from Toys R Us, that contains a spoiler, for the second half of season three. The tweet and poster are embedded below.
Looks like Saw Gerrera is coming to #StarWarsRebels soon! @CoffeeWthKenobi #RogueOne pic.twitter.com/MMYcwr2TN5— Rebels Reactions (@RebelsReactions) December 17, 2016
The second half of season three of Star Wars Rebels is scheduled to begin next month. At this point, it seems Gerrera will play a role in the upcoming episodes, and since he so prominently featured in the poster, it may be a large role. Perhaps, we will see the extremist actions that lead the Rebel Alliance to part ways with him, that were hinted at in Rogue One.
Gerrera first appeared in four episodes of season five of Star Wars: The Clone Wars.