During a panel for the show at Stan Lee's Comikaze, executive producer Danny Cannon revealed writers are currently working on an episode that introduces Scarecrow.
"We're breaking the story now," Cannon says. On "Gotham," the villain will be seen as a child, before he takes on the Scarecrow moniker. In fact, it's something that will be passed on to him from his father, which will create an eventual enemy for Batman while still having a possible adversary for Jim Gordon."
No info on when or if it will even be this season.