President-elect Donald Trump is expected to appoint Florida Sen. Marco Rubio as secretary of state for his administration in the coming days, according to three sources familiar with the selection process.

Trump could still change his mind, the sources warned, noting that the decision would not be final until the president-elect makes a formal announcement.

The New York Times first reported Trump’s plans to appoint Rubio as the country’s top diplomat.

Foreign policy is one of the few areas where there are deep philosophical disagreements among Trump’s base.

A key argument made by Trump during the campaign was that he would implement an “America First” policy, a doctrine that emphasizes less foreign aid, in an effort to limit U.S. involvement in current foreign conflicts and avoid future conflicts. But even among prominent Trump supporters, there remains a shift in thinking about foreign policy.

Although Sen. Marco Rubio, R-Fla., is an outspoken Trump supporter, the perception is that he was one of the “less MAGA” options, as a Trump ally told NBC News. It’s a position that should be sufficiently attractive to Trump’s more isolationist political base, but also bear water for the less disruptive kind of foreign policy that Trump supporters tend to oppose.

Rubio, a member of the Foreign Relations Committee, was seen as a potential pick who could appeal to Trump’s political base without unnecessarily eroding relations with foreign allies.

One Trump ally said Rubio was someone “Trump’s base could trust.”

“While Marco is slightly more aggressive than the incoming president and vice president, he is actually not as far removed from them as many people might initially think,” said another Trump ally. “He has become much more aligned with the president on issues related to tariffs. He has a similar position on the China issue and even voted against the latest round of funding for Ukraine.”

A current senior administration official told NBC News that Rubio would be a “serious” and “qualified” choice. The person said a Rubio pick would be a relief given reports that Ric Grenell, the highly controversial ambassador to Germany during Trump’s first term, had also been under consideration. Several career diplomats said they were concerned that the State Department would become politicized if Grenell were nominated.

Under the last Trump administration, the number of diplomats in senior ranks at the State Department plummeted, first through voluntary departures shortly after his election and later through attrition as the authority of their positions was shifted to political appointees.

Trump had previously considered Rubio as a running mate before ultimately choosing Sen. J.D. Vance, R-Ohio.

If Rubio becomes secretary of state, Florida Governor Ron DeSantis would be allowed to choose a replacement. That choice would last until at least 2026, when elections for the seat would be held.

Trump has made a series of other personnel announcements in recent days. On Monday, he announced plans to appoint former Rep. Lee Zeldin, R-N.Y., as the top administrator of the Environmental Protection Agency and to name Rep. Mike Waltz, R-Fla., as his national security adviser.

Last week he said Susie Wiles, his campaign manager, would become White House chief of staff. On Sunday, he called immigration hardliner Tom Homan his “border czar.”