Warner Bros.' long-awaited "Justice League" movie may have hit another speed bump on the long road to the big screen -- and it could be Superman's fault.

While "Justice League" -- which would unite Superman, Batman, Wonder Woman, and other DC Comics heroes -- still seems to be moving ahead full steam, new reports indicate that "JL" won't officially get the fabled green light until Warner Bros. sees the box office receipts for this summer's Superman reboot "Man of Steel."

According to a Variety article about successful Warner Bros. motion picture group president Jeff Robinov's future plans at the studio, a "Justice League" movie wouldn't be seen anytime before 2015, because "Warner's top brass has indicated that they are awaiting the results of 'Man of Steel'...before moving further ahead." 

The studio is understandably a little bit shy about sinking a significant chunk of change into a "JL" movie if "Steel" underperforms the same way that 2011's "Green Lantern" did. However, the project has been in development on and off again for years now, and recent news indicates that the studio is finally, really, truly moving ahead with "Justice League," so we'd hate to see them pull the plug on it now. 

"Man of Steel," directed by Zack Snyder and starring Henry Cavill as Superman, opens June 14.