Trump's first NSA, Michael Flynn, resigned past year after holding the post for just a month amid controversy over his contact with Russian officials over their alleged meddling in the 2016 USA presidential elections.
Keen to avoid a public scene of another top official's ouster, the plan may include giving McMaster a fourth star and sticking him in another military post, which might well be in Afghanistan.
"It was a tremendous day, and to a large extent because of what I witnessed, we may do something like that on July 4th in Washington", Trump was quoted as saying when French President Emmanuel Macron visited Washington two months later.
Despite Trump's early-morning, impromptu ban on transgender troops in the military, Mattis is expected to back them staying in a report to the White House. Trump wants everything laid out for him like a puzzle from a Highlights magazine because he simply isn't capable of understanding anything more complex than that. "Any decision with regards to staff, the White House will make those determinations", said Pentagon spokeswoman Dana White.
CNN previously reported that McMaster appeared to be undercut last summer by former chief strategist Steve Bannon.
Several courts have blocked the ban from coming into force while lawsuits against it are pending.
"He paid McMaster back by spreading rumors and whispering in Trump's ear", the senior Republican source said, adding that "Bannon poisoned the well".
Some officials have told CNN that the Pentagon may be looking to identify a slot that is not too high profile, because McMaster would be transitioning back to the military from a White House position akin to a political appointee.
"The recommendations were a private conversation between the secretary and the White House, and the contents will remain private", Eastburn said.
The defense secretary was scheduled to brief the president Wednesday, but the meeting was postponed and will occur soon, officials said, speaking on the condition of anonymity to discuss policy deliberations.
A Rand Corp. study commissioned by the Pentagon ahead of its 2016 policy change found that there were 1,320 to 6,630 transgender service members among 1.3 million people on active duty - less than 1 percent of the force.
If a suitable job couldn't be found, McMaster could opt to retire.