We've already learned from the Batman v Superman: Dawn of Justice trailer that Robin will play some role in the story. There's a brief scene in which we see Robin's suit in the Batcave with a sinister note from the Joker that says "Hahaha Joke's on you Batman."
It's safe to assume that there will be a flashback scene that shows the audience what exactly happened to Robin and how he was killed. According to Heroic Hollywood, this version of Robin will be played by director Zack Snyder's son Eli.
This wouldn't be the first time that Eli has had a small role in one of Snyder's films. He also played the young Leonidas in 300 and young Rorschach in Watchmen. The kid is 6-feet-tall and a starting Quarterback, so he has the physique and athletism to take on the role of Robin.
There's no official confirmation of this casting, but I wouldn't be surprised if it turned out to be true.