Miller:

Equally central to my decision was Mr. Fitzgerald, the prosecutor. He had declined to confine his questioning to the subject of Mr. Libby. This meant I would have been unable to protect other confidential sources who had provided information - unrelated to Mr. Wilson or his wife - for articles published in The Times. Last month, Mr. Fitzgerald agreed to limit his questioning.

Huh?  Fitzgerald wanted to question Miller about sources unrelated to Mr. Wilson or his wife? I don't doubt there were other sources Miller wanted to protect, but the assertion that they were unrelated to the case seems implausible.

Miller's next sentence flatly stated that without Fitzgerald agreeing to limit his questioning she "would still be in jail."

So it is clear that Miller had sources she wished to protect, people other than Libby.

Mr. Fitzgerald asked if I could recall discussing the Wilson-Plame connection with other sources. I said I had, though I could not recall any by name or when those conversations occurred. 

Are these the same sources she was willing to have stayed in jail to protect?  Would she not be willing to lie to protect them, then?