Who's next? Here are 9 potential replacements for John Kelly

Robert Lighthizer, the current US Trade Representative, was also reportedly among the names Trump floated around. However, The Washington Post reported that some in the White House are reluctant to move Lighthizer from his key role in China trade negotiations.

Lighthizer, who landed in the Trump White House in May 2017, said in a Sunday interview with CBS's "Face the Nation" that he believes Kelly has "done a great job for the president."

When asked if he would want the role of chief of staff, Lighthizer said "the president has given me what is a very difficult job," adding that he has not been approached by anyone in the White House for the chief of staff job.

"I haven't spoken to anyone," he said. "I'm entirely focused on what I'm trying to do, and it's difficult enough."

Steven Mnuchin, the Treasury secretary, has also been floated around as a potential chief of staff, according to Reuters.

Reuters reported that Mnuchin, who has served the administration since February 2017, sees his role as Treasury secretary as best suited to help the president. However, The Washington Post reported that Mnuchin might change his mind and take the chief of staff position if Trump pleads with him.

The Associated Press reported that Mick Mulvaney, current White House budget chief and acting director of the Consumer Financial Protection Bureau, is back again as a contender for the chief of staff role after Trump briefly considered replacing Kelly with him over the summer.

Mulvaney, the AP reported, is not interested in the position and would rather serve as Treasury or commerce secretary.

Former New Jersey Gov. Chris Christie, once a challenger for Trump's bid for the Republican presidential nomination, has been floated, according to The New York Times.

Christie, the Times said, is a former United States attorney who could come in helpful in the face of a potential impeachment fight. Christie has said nothing about a potential chief of staff nomination but spent his Sunday talking about what Michael Cohen's indictment might mean for the president on ABC's "This Week."

"The only thing that would concern me if I was the president's team this morning about this sentencing memo is the language," Christie said. "The language sounds very definite."

NBC News first reported that Randy Levine, the president of the New York Yankees, as a contender for Kelly's job on Monday. Levine, who comes to this race out of left field, served in then-New York City Mayor Rudy Giuliani's administration and was an associate attorney general under President Ronald Reagan.

Despite the speculation, Levine told Fox News he hasn't spoken to anyone in the White House about the chief of staff job.

"I have great respect for the president, but am very happy being president of the Yankees," he said.

David Bossie, Trump's former deputy campaign manager, is also an option, according to the Wall Street Journal.

Bossie, who continues to advise Trump, cowrote two books on the Trump White House with Corey Lewandowski, Trump's former campaign manager. Bossie is currently chairman of conservative advocacy group Citizens United.

He was briefly suspended as a regular guest on Fox News programs over the summer after saying an African-American guest was "out of his cotton-picking mind."

Blackstone Group senior adviser Wayne Berman made the shortlist, according to Politico.

Berman served as a top political aide at the Commerce Department under President George H.W. Bush and was also named as a potential replacement for Reince Priebus before Trump selected Kelly.

Berman has previously worked for various presidential political campaigns, including as chair of Sen. Marco Rubio's 2016 campaign as the national finance chair for John McCain's 2008 run for president. According to CBS News, Berman has no direct personal or professional connection to Trump, which may actually work in his favor.

Matt Whitaker, Trump's acting attorney general, might soon need a new job after the president nominated William Barr to the attorney general position.

That's why several publications, including The Washington Post, have identified him as a strong contender for Kelly's position.

Whitaker, who was scrutinized widely after being named as the acting attorney general, has publicly opposed the Russia investigation and remains close to the president, attending the Army-Navy football game with him on Saturday.