ABC News’ Martha Raddatz reports: In a letter to the troops in Iraq, the top U.S. commander, Gen. Ray Odierno says that "following an initial drawdown over the next six months, our forces will remain at a robust level through the critical time leading up to and immediately following Iraq’s national elections in late-2009/early-2010." ABC News has learned from Defense Department officials that early indications are that the initial drawdown Gen. Odierno is referring to will consist of two brigade combat teams or the equivalent of 8,000-10,000 troops. That small drawdown will leave the large "robust force" Odierno wants to have in place for the regional elections this summer and the national election in December, 2009. It also means that a significant portion of the 142,000 troops currently in Iraq will remain in place the remainder of this year. These officials tell ABC News that the next series of combat troop drawdowns would begin in January-February of 2010, after the national election. That would require a huge logistical undertaking to reduce force levels by today’s announced target date of August 31, 2010 to the 50,000 minimum. ABC News has also learned that Gen. Odierno will receive a Stryker Brigade to replace the one diverted to Afghanistan just a week ago. That means that he will continue to maintain the current level of two Stryker brigades in Iraq. The light armored vehicles are favored by military commanders for their mobility as a quick reaction force while providing greater protection for the troops. The current Status of Forces Agreement requires all US forces to be out of Iraq by the end of 2011, though the possibility remains the agreement could be re-negotiated. After the President’s speech today in Camp Lejeune, Defense Secretary Robert Gates told reporters that while that possibility was just a hypothetical, "my own view would be that we should be prepared to have some very modest-sized presence for training and helping them with their new equipment and providing perhaps, intelligence support and so on beyond that.” Gates has made similar comments prior to the finalization of the SOFA deal late last year. Editor’s Note: Over the weekend, additional information led us to rework this article. We have restored the original wording as additional reporting reconfirms the information posted Friday night. Gen. Odierno will maintain a two-Stryker Brigade presence through the rest of this year even though a replacement Stryker Brigade had been redirected to Afghansitan. The Pentagon’s announcement Monday that the 4th Stryker BCT, 2nd Infantry Division will head to Iraq in the Fall means both brigades currently in Iraq will be replaced by Stryker Brigades. In shorthand, the 4th SBCT/2nd ID will replace the 1st SBCT/25th ID and the 3rd SBCT/2nd ID will the 56th National Guard Stryker Brigade.