Michael Dougherty and Dan Harris head different directions

Bryan Singer is going to have to find some new screenwriting buddies for his "Superman Returns" sequel.

According to Variety, "Superman Returns" writers Michael Dougherty and Dan Harris won't be back for the sequel, which was most recently being called "Man of Steel."

As recently as July, Variety had claimed that Singer had pitched Warner Bros. on the sequel and that Dougherty was on board to write. The trade also said that Kevin Spacey would be back for another turn as Lex Luthor.

Not so fast.

The trade is now saying that as Warner Bros. looks for a new Superman for the studio's "Justice League of America" movie, it's unclear what form the "Superman Returns" sequel would take. Studio sources tell the trade that there are no plans to reboot "Superman" in the same manner Marvel is doing with both "The Hulk" and a new "Punisher" movie and that Brandon Routh's return "likely."

The simple explanation for Dougherty and Harris' departure is reportedly just about timing and scheduling. Dougherty just finished making his directing debut on "Trick 'R Treat," while Harris is working on an adaptation of "I, Lucifer" for his second time behind the camera.