"Creatively, I really feel like I gave it my all, and I feel ready to let her go," Oh told The Hollywood Reporter.
"It's such an interesting thing to play a character for so long and to actually get the sense that she wants to be let go as well. [My character Cristina] wants to be let go, and I am ready to let her go. We have to start the process, story-wise, for the 'Grey's' writers to think of why she's going to go."
UsMagazine.com said Oh has earned five supporting actress Emmy nominations for her work on the series. Her film credits include "Sideways" and "Under the Tuscan Sun."