Rob Williams is currently in panel talking about the mainline Suicide Squad series that is incoming from DC Comics. In it, he has just outlined some of the ground rules for the comic.

He confirmed that each issue will contain two stories, one 12-13 page story focused on the squad, and one 7-8 page profile of one of its members. It's said that the main line story is about the Squad finding an artifact while on a mission that will change the team's outlook. He then added that the squad gains a member "but it's not a new member that you'd expect going to join the Suicide Squad."

So, have at guessing I suppose.