After watching the January trailer of Suicide Squad I began to wonder if the Joker was actually going to be on the Suicide Squad with Harley Quinn or if he was actually going to be a villain. I could be wrong and maybe he’ll be on the team but he’ll just be the loner always kind of off from the rest of the team. However, in this trailer we see the Joker with what might be his Joker gang and still nothing with the team.
I have heard it argued that Batman takes down the Joker all the time by himself so they wouldn’t need an entire team of super villains working for the government to apprehend him. But that really isn’t enough to discount it for me. Especially if he’s just one of the antagonists. It is also possible that Batman gets captured by the Joker and is being tortured until he can either escape or be rescued by the Suicide Squad.
I also saw it suggested that the Enchantress will be one of the main villains. I can’t really confirm or deny that. Their speculation seemed to come from her interacting with her brother and trying to resurrect someone. But that could be anything–including something she’s doing while working with the team. So we shall see.