Now, according to Collider.com, there's a rumor saying that The Batman himself was in attendance but behind closed doors. One of Collider's readers emailed the site saying a football player actor disclosed info saying Ben Affleck filmed a motivational speech to the Gotham players in the locker room prior to the football plays being filming on the field. Affleck was not in costume as Batman but instead he was Bruce Wayne.
Other reports from the football stadium filming include the fact that Warner Bros. representatives were referring to the movie as "Batman vs. Superman" and that the football scenes may be the very beginning of the film.
Batman vs. Superman releases in theaters on July 17, 2015.