Washington (CNN) With tensions flaring between President Donald Trump and national security adviser Lt. Gen. H.R. McMaster, the Pentagon is considering options that would allow the President to potentially move the three-star general out of his current role and back into the military, according to half a dozen defense and administration officials.

A search is quietly being conducted by the Pentagon to see if there is a four-star military job suited for McMaster, these officials said.

Several sources told CNN that the push for a replacement comes after months of personal tension between McMaster and Trump. The task of easing McMaster out of his role as national security adviser presents a unique challenge for the White House.

While administration officials have privately said the preference is to move McMaster into a position within the Army or Defense Department that qualifies as a promotion, some within the Pentagon feel he has become politicized in the White House and have expressed reservations about him returning to the military in a prominent role. Some defense officials caution that the President could also go as far as not to offer him a fourth star and force him to retire.

This is not the first time McMaster has faced speculation that his job may be in jeopardy and sources with knowledge of McMaster's standing in the White House have repeatedly said that he has been on thin ice for months.

There was discussion in the West Wing about replacing him last fall, but he ultimately survived because officials, including the President himself, were skeptical about the optics of appointing a third national security adviser in less than a year, several sources told CNN. Trump's first national security adviser, Michael Flynn, resigned amid controversy over his contact with Russian officials within a month of taking the job.

The decision was also driven by the White House's challenge attracting top talent for jobs in the administration due to Trump's "blacklist" of individuals who have criticized the President, his personality and the Russia investigation, according to a senior Republican source.

However, those familiar with the President's thinking don't believe McMaster's job is any safer now. "He is safe until he's not," the senior Republican with knowledge of the White House added.

On Thursday, the Pentagon referred all questions about McMaster's future to the White House.

"General McMaster works for President Trump. Any decision with regards to staff, the White House will make those determinations," chief spokesperson Dana White said.

The White House did not respond to CNN's request for comment. White House press secretary Sarah Sanders said Tuesday that Trump "still has confidence in General McMaster."

Tension with Trump

Tensions between Trump and McMaster have been playing out for months and were on full display this weekend after Trump publicly chided him over remarks he made regarding Russian interference in the election.

"General McMaster forgot to say that the results of the 2016 election were not impacted or changed by the Russians and that the only Collusion was between Russia and Crooked H, the DNC and the Dems," Trump tweeted. "Remember the Dirty Dossier, Uranium, Speeches, Emails and the Podesta Company!"

The criticism laid bare the strained relationship between the two men and left some wondering how much longer McMaster has left in the administration. For months, Trump has privately expressed irritation with McMaster stemming from differences in "personality and style," the senior Republican source said.

The two have never gotten along, and Trump continues to chafe at McMaster's demeanor when he briefs him, feeling that he is gruff and condescending, according to a source who is familiar with his thinking.

He prefers the briefing style of someone like CIA Director Mike Pompeo or Defense Secretary James Mattis, who patiently answer his questions, regardless of the premise. McMaster, meanwhile, is the person who delivers the news that Trump doesn't want to hear on a daily basis, according to the senior Republican source.

The issue is not political but mostly stylistic, as McMaster and Mattis tend to discuss information before it is presented to the President, the same source added.

CNN previously reported that McMaster has been at odds with the President and other cabinet officials over the last year.

He has also been undercut by others in Trump's orbit like former chief strategist Steve Bannon, according to congressional and administration officials. A source familiar with the situation said Trump's perception of McMaster is still influenced by the legacy of Bannon who maintained a tense relationship with McMaster after McMaster removed him from the National Security Council.

"He paid McMaster back by spreading rumors and whispering in Trump's ear," the senior Republican source said, adding that "Bannon poisoned the well."

What's next for McMaster?

Officials could not yet confirm what job McMaster might be nominated for if he were to leave the White House.

The current commander of US forces in South Korea, General Vincent Brooks, is expected to leave his post on a scheduled rotation in the coming months but his successor has already been earmarked within the Army but not yet made public, several officials said.

Another possible option would be to name McMaster as the replacement for Gen. John Nicholson who has served as commander of the coalition in Afghanistan since 2016.

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.

If moved back into a military role that involves testifying before Congress, McMaster might be viewed as simply supporting the White House rather than providing lawmakers with his best military advice, one defense official said.

Lawmakers on the Senate Armed Services Committee would likely have questions about McMaster's time in the White House should he be nominated for a military role but an aide to one senior Republican member told CNN that there do not appear to be any obvious red flags at the outset that would inherently prevent his confirmation.

A second defense official said McMaster is well aware of those political sensitivities.

However, one top Pentagon official said McMaster's role in the administration should not prevent him from earning his fourth star, comparing his transition to other military officers like Colin Powell who have gone back and forth between the Pentagon and the White House.

McMaster would also have the option of retiring from active duty at any time if he chose to do so.

But officials told CNN that the White House's wish is to find McMaster a four-star job that is seen as acknowledging his service.