Creator Eric Kripke had intended the series to end after its original five-year story arc was complete. However, it was later announced that the drama would return for a sixth season.
Ostroff told reporters at the Television Critics Association press tour: "I think we're all feeling really enthusiastic about Supernatural. Everybody on the show still feels that there's a lot of juice left in the characters, and we hope it goes on for more seasons, for sure."
Series stars Jared Padalecki and Jensen Ackles are currently only contracted until the end of the sixth season.
Ostroff also revealed that the show would return to the storytelling format of the first season, featuring standalone episodes and one-off villains.
"I don't know if you saw the show in the first season, but... they were hunting something different every single week, and they're going to go back to that format," she confirmed. "The one twist aside from the guy's personalities kind of changing a bit is that their mother's side of the family is going to turn out to be hunters also, and so there'll be some storylines involving [her] side of the family."
The sixth season of Supernatural begins September 24 on The CW.