[Via The New York Post.] According to co-star James Pickens Jr., who plays the chief, Katherine Heigl and T.R. Knight are leaving Grey's Anatomy. With this news, I hope that Izzie Stevens dies (because allowing her to survive a fatal disease would be copping out), but I wonder how George O'Malley would be written out. Perhaps he gets a job elsewhere? There has been talk that Denny might come back, so perhaps when Izzie "crosses over" she'll be visited by him again, though I doubt the writers will handle the scene with intelligence. Sometimes I feel like the Grey's writers are better at the guests' storylines than their own stars'.
At any rate, I'm happy with this news, not because I dislike either actor (I actually adore Katherine Heigl) but because the show's character relationships are becoming too convoluted and the cast is overcrowded.
Update, 5:10pm: According to Kristin over at E!:
However, a well-placed ABC source tells us, "There's no way [Pickens] could know that, because nothing has been decided yet. Nothing has been written and [Heigl and Knight] are still working out what will happen next season with the network."
According to inside sources who work on Grey's, it is likely that Heigl and Knight will make an exit at the end of the current season. Both have asked to leave the show. However, ABC needs to sign off on letting them out of their contracts, which has not been done.