Polygon was able to acquire a picture of a promotional poster for Injustice 2. The poster features both The Flash and Batman with the tagline “Every battle defines you.”
The site also reported that a note was given to managers saying the posters are pre-order bonuses for those who decide to pre-order the game while supplies last. There are rumors that this was an error of GameStop’s behalf as they sent them out before an announcement or a street date was revealed.
Expect the official announcement at E3.