Introduced in Gilmore Girls' pilot, Dean Forester was a key figure in the early part of Rory Gilmore's story. However, even though Dean was one of Rory's more important romantic interests, he didn't appear on the CW series after Season 5. His surprising absence had a lot to do with the actor who played Dean's character, Jared Padalecki, and his career trajectory, which led him to another CW project.
Source：https://www.cbr.com/why-jared-padalecki-dean-left-gilmore-girls/
