Khalilzad leaving Baghdad?

This is a mysterious twist.  Someone is leaking the story that the current US Ambassador in Baghdad, Zalmay Khalilzad, is planning to resign his post probably sometime early next year:  U.S. envoy to Iraq likely quitting post by Anne Gearan AP 11/06/06.  Gearan reports:

His replacement in Baghdad may be Ryan Crocker, a senior career diplomat who is currently U.S. ambassador to Pakistan, those officials said. Crocker was a top U.S. representative in Baghdad for several months in 2003, shortly after the U.S.-led invasion that toppled Saddam Hussein. ...

National Intelligence Director John Negroponte, during a Baghdad visit on Friday, told al-Maliki that Khalilzad would leave about the first of the year and replaced by Crocker, according to two top aides to the Iraqi leader. The aides spoke on condition of anonymity because they are not authorized to release information.

If that source is accurate, I wonder why it would be John Negroponte, the Director of National Intelligence (DNI) that would bring the message to Maliki instead of sending it through regular State Department channels.  I don't know the exact protocol on these things.  But I'm guessing that's not it.

Dan Senor gives us the following information on Crocker in a column on the recent book by Rajiv Chandrasekaran, The Realities Of Trying to Rebuild Iraq  Washington Post 10/10/06:

Nor does Chandrasekaran discuss Ryan Crocker, a striking omission since Chandrasekaran once described Crocker as Bremer's "top political aide" [news story, July 13, 2003]. Crocker, the senior State Department official with responsibility for Iraq before the war, led the CPA's political reconstruction team. A fluent Arabic speaker widely regarded as among the State Department's most distinguished Arabists, Crocker had served as ambassador to Syria and Kuwait under Clinton. He is a consummate professional diplomat, neither inexperienced nor an ideologue. And he was extraordinarily influential in the early months of the occupation; along with Bremer and senior British envoy John Sawers (another Middle East expert, who had cometo the CPA from his post as ambassador to Egypt), Crocker played the most influential role in selecting the Iraqi Governing Council in July 2003. But reading Chandrasekaran's book, you would be left with the impression that Crocker had nothing to with Iraq - he does not even get a mention.

Crocker, in other words, was one of the most important officials making key decisions in the early months of the occupation, a period which is now widely regarded as having squandered whatever possibilities were there for the Iraq War to turn out as some less than a complete disaster for the United States.  Another heckuva job guy, apparently.