That's the rumor at the Pentagon according to the New York Times:
The Pentagon is considering Gen. David H. Petraeus for the top NATO command later this year, a move that would give the general, the top American commander in Iraq, a high-level post during the next administration but that has raised concerns about the practice of rotating war commanders.... Some experts, however, say General Petraeus's departure would jeopardize American efforts in Iraq, especially since the No. 2 officer in Iraq, Lt. Gen. Raymond T. Odierno, is scheduled to complete his tour and leave Iraq in mid-February. General Petraeus "should stay at least through this year," said Anthony Cordesman, a military specialist at the Center for Strategic and International Studies. "We really need military continuity in command during this period in which we can find out whether we can transition from tactical victory to some form of political accommodation. "We have in Petraeus and Crocker the first effective civil-military partners we have had in this war," Mr. Cordesman added, referring to Ryan C. Crocker, the United States ambassador in Baghdad. Gen. George W. Casey Jr., General Petraeus's predecessor, served nearly three years in the top Iraq job before becoming Army chief of staff.
Why would we rotate Petraeus out of Iraq before January 20, 2009? He's had remarkable success as the commander of U.S. forces in Iraq, and Cordesman's emphasis on the effective collaboration between Petraeus and Crocker is another compelling reason for the administration to resist any change to the current arrangement. One would think that 'don't fix it if it ain't broke' is the best maxim to apply in evaluating the command structure in Iraq.