The Rev. Canon Mark Harris writes at Preludium:
The Presiding Bishop does not use words carelessly. She has said two things: (i) She “at present” does not believe she should serve and lead in this ministry for another nine years, and (ii) there is the implicit expectation that any candidate should be ready to serve a full term.
She also broadened her comments to say that “I believe I can best serve this Church by opening the door for other bishops to more freely discern their own vocation to this ministry.” So she really is making the process more clearly open to bishops who might otherwise stand back if she was willing to serve another nine years.