Mark Hughes from Forbes says he has heard from a source that "Batman will appear in Suicide Squad, supposedly in an in-story scene, likely at the end of the film and focused on certain circumstances involving the Joker (POTENTIAL SPOILERS BELOW)."
Hughes says Batman's inclusion is being done to setup Ben Affleck's first solo adventure as The Caped Crusader. He has heard that it will be inspired by Frank Miller's 1986 four-issue comic book mini-series The Dark Knight Returns - "the third issue of which is a story about Batman facing off against an escaped Joker." Which would make sense if the rumors, about them doing a female robin are true! Since there was a female robin in Frank Millers comic series.
Hughes also says Gotham City Police Commissioner Ellen Yindel, who was Jim Gordon's successor in Milller's The Dark Knight Returns story arc, will also appear in the solo film. In the comic, she doesn't trust Batman like Gordon did. Though, some tragic events maker her softer her stance on Batman. Her inclusion could make for a new and interesting relationship between Batman and the GCPD.
Suicide Squad will land in theaters Aug. 5, 2016.