That's according to showrunner Andrew Kreisberg, who mentioned the character in passing when referencing upcoming storylines on an episode of Kevin Smith's Fat Man on Batman podcast (via
Bizarro is lumped with longtime Superman baddie Toyman, but since so much of Supergirl has been based on Sterling Gates and Jamal Igle's acclaimed run on Supergirl, it seems more likely that we'll see the female version of Bizarro pop up.
In Gates and Igles Bizarrogirl story in Supergirl, the character came from "Bizarro World," a planet called Htrae that was like a fractured mirror image of the DC Universe. It isn't immediately clear whether that version of Bizarro will make it to air, or if the somewhat easier-to-translate take from John Byrne's The Man of Steel -- that Bizarro was an imperfect clone of Superman -- will be used. In Bizarro's earliest appearances in Superboy, that was roughly his origin before the concept of Bizarro World was introduced two years later.
In Batman V Superman: Dawn of Justice, they appear to be riffing on that version, with Doomsday being the product of Luthor's genetic manipulation of General Zod's corpse.