Nick Ayers, who is now chief of staff for Vice President Mike Pence, is the front-runner to replace Kelly, according to Axios and ABC News. Vice President Mike Pence's chief of staff, Nick Ayers, is a possible contender, the source said. Ayers was important to Pence's arrival on the Trump ticket, worked at a high level on the transition and is considered deeply loyal to the Trump agenda. But there is a holiday senior staff dinner scheduled for Friday night and people said they expected Kelly to be there.
Kelly reportedly intervened to stop Trump firing Department of Homeland Security Secretary Kirstjen Nielsen last month.
Trump nominated him for a second two-year term last year.
Trump had earlier pledged publicly that Kelly would remain through his first term in office, though many in the West Wing were skeptical. In recent months, the chief of staff's power has ebbed, with administration policies and decisions being guided more by the president's gut instincts than by Kelly's processes.
Trump often vacillated between criticizing and praising Kelly, sometimes within minutes of each other.
At times, Kelly was the source of his own downfall.
It is unclear who the replacement would be.
State Department spokeswoman Heather Nauert has been nominated as the next USA ambassador to the United Nations. He is supported by Jared Kushner and Ivanka Trump, the president's son-in-law and daughter, who both serve as senior West Wing advisers and who, according to several officials, are trying to expand their influence internally and in the re-election campaign.
Nauert, 48, joined the State Department a year ago with no government experience after a career as an anchor and correspondent at Fox News.