In an interview with the BBC, Transformers: Revenge of the Fallen and Indiana Jones and the Kingdom of the Crystal Skull star Shia LaBeouf indicated that a fifth Indiana Jones movie was a definite possibility, telling the BBC: “Steven (Spielberg) just said he cracked the story on it before I left, and I think they're gearing that up.”

 

LaBeouf played Indiana Jones’ son Mutt in the fourth Indy film, which grossed $783 million worldwide in spite of generally poor reviews.  That sort of box office performance is certainly enough of an incentive for Spielberg to want to bring the franchise back, though typically Indy movies have a very long gestation period, and no one is at all certain that Harrison Ford will back as the fedora-topped adventurer.  If Ford opts out, the franchise could continue with LaBeouf who has certainly demonstrated with the Transformers movies that he can carry a summer blockbuster by himself.