The so-called "zero option" would mean abandoning plans to leave a residual U.S. troop presence in the country once American commanders end all combat operations within the next year and a half.
A final decision on the American postwar presence in Afghanistan is expected no later than November, Rhodes said, adding that administration officials would have a "better idea" on when that decision would come down as negotiations with Kabul continue.
That said, the administration "will not rule out any option" to meet President Obama's goals of ending U.S. operations in Afghanistan by 2014 and ensuring Afghan forces can maintain security in the country, Doug Lute, the White House's coordinator for South Asia, added.
While the zero option is on the table, "there are a range of ways [with] ... a range of consequences associated" that White House decision makers are considering to meet the president's goals, Lute said.
That said, any option for a U.S. postwar presence in Afghanistan being weighed by the White House will ensure that as Afghan forces "stand up, they will not stand alone," Rhodes added.
Both officials' comments come as the Obama administration is preparing for a week-long visit by Afghan President Hamid Karzai to Washington.
Arriving late Tuesday evening, Karzai will meet with the president to discuss a number of issues surrounding the White House's drawdown strategy.
Along with the president, Karzai is also expected to sit down with Defense Secretary Leon Panetta and Secretary of State Hillary Clinton to hash out the details of the coming U.S. troop withdrawal and America's role in Afghanistan post 2014.
While the war will likely take center stage during Karzai's visit, Lute dismissed any notion this week's meetings would somehow produce a decision on final U.S. troop numbers.
"We are talking about missions and authorities, not numbers," he said, with the administration focusing on the specific missions of training and advising Afghan forces while continuing counterterrorism operations in country.
But details of the Pentagon's early assessments of U.S. postwar options, reported by The New York Times, claim those missions would require keeping roughly 10,000 American service personnel in country after 2014.
That assessment, drafted by Gen. John Allen, the top U.S. commander in Afghanistan, is one of many included in the four-star general's slate of postwar recommendations sent to Panetta late last year.
One of Allen's post-2014 scenarios includes keeping a 6,000-man U.S. force in country, assigned strictly to carry out operations against al Qaeda, Taliban and other militant Islamic cells based in Afghanistan.
He also proposed a much larger 10,000- to 20,000-man force that would conduct counterterrorism missions, help train the Afghan National Security Forces and continue a small number of the conventional combat operations currently being executed by U.S. and NATO forces.
Lute declined to comment on whether the White House's focus on counterterrorism and training missions meant the president was leaning toward the 10,000-troop option.
"I do not want to lend any credence to those numbers," he said.
Any troop number assessments being floated in Washington are "reflective of the different assumptions about the variables" counterterrorism and training operations, which are all in flux, Lute noted.
On Thursday, DOD press secretary George Little warned reporters at the Pentagon not to draw any "grand conclusions" over reported troop assessments, adding that Panetta has yet to provide his own recommendations to the White House on the postwar strategy.