"We're putting our thoughts together now," Mattis told reporters in Abu Dhabi, where he is travelling to now after cancelling his Afghan trip due to bad weather.
"The President has been rightly reticent on it, because he's waiting for my assessment, and the assessment from the intelligence community. And he's open to my advice on it," he said in response to a question.
"But first of all I've got to formulate where I stand, and so this is the normal collection of the information, and to assess what the other countries in the region are doing in Afghanistan to help or hinder us in our efforts there," the Defense Secretary said.
On the Taliban, Mattis said "they know they cannot win at the ballot box and are using bombs and guns on purpose. They were unsuccessful in gaining their tactical objectives."
"So, I think it was a lot more damaging to the Taliban and the Afghan security forces paid a very heavy price to keep the Taliban on the back foot. The Taliban is in a worse position today, even though I do not equate that to success on our side," he added.