Many things have changed since President Obama announced in May that the U.S. would leave no more than 9,800 troops in Afghanistan next year.

And now that decision may be getting a second look.

The new commanding general in Kabul, Army Gen. John Campbell, is reviewing plans for officially ending the 13-year Afghanistan War to make sure that the troop numbers, timeline and overall strategy still makes sense, military officials say.

"Right now, he is comfortable with the current plan and timeline," said one military official in Afghanistan. "This being said, there are variables which need to be considered."

Campbell is assessing an array of new developments over the past several months, including the end of this year's fighting season, the impact of the long-delayed presidential election in Afghanistan and the assent of a far more pro-American president, and the final inking of a bilateral security agreement that gives U.S. troops legal authority to stay.

In the short term, Campbell said he's comfortable with this year's remaining drawdown that will bring today's force of about 18,000 to 9,800 by the end of December.

But looking into the future, he may recommend adjustments to the long-term plan that Obama announced in May that will leave a small contingent of U.S. troops in Afghanistan for the next two years — about 9,800 in 2015 and about half that in 2016. Plans call for ending the U.S. military mission by 2017.

"Do I come back and do I alert my leadership and say, 'We are coming down to this number, we need to hold a little bit longer to take advantage of some of the things that President [Ashraf] Ghani has put in place and we need more NATO forces in certain locations for longer?' " Campbell said. "I've got to do that analysis and we're just starting that now."

Campbell will take a close look at the current state of the Afghan army. So far this year, Afghan military and police forces have suffered more than 4,600 fatalities.

"This is not sustainable," Lt. Gen. Joseph Anderson, a senior commander for U.S. and NATO forces in Afghanistan, told reporters Nov. 5. "They do need to decrease their casualty rate."

Obama in May announced plans to leave a small contingent of U.S. troops in Afghanistan for the next two years — about 9,800 in 2015 and about half that in 2016. Plans call for ending the U.S. military mission by 2017.

Since then, the U.S. strategic focus has shifted back to Iraq, where Iraqi soldiers deserted in droves in June and Islamic militants seized control of several large cities. The crisis has led many military officials to second-guess the 2011 decision to not leave a large contingent of American troops in Iraq.

Inevitably, comparisons are made to the current situation in Afghanistan, prompting some military experts to question whether the U.S. should ratchet up its commitment to support the Afghan security forces in the fight to defeat the Taliban insurgency.

But the military official in Afghanistan said Campbell has been on the job there for less than three months and has not had time to conduct a complete review of those long-term plans.

"It is too early to make any sort of long-term recommendation. As conditions change and perhaps warrant a recommendation to adjust/change the plan, then he will provide an assessment and send a recommendation to his chains of command for consideration," the official said.