A year later, has Chief of Staff John Kelly reached his expiration date? President Trump predicted Kelly would remain seven years. That's now in doubt.

One year ago, President Trump installed Marine Corps Gen. John Kelly as his second chief of staff, a move widely seen as an effort to impose order, discipline and workflow on a chaotic inner circle that had grown unwieldy in the West Wing.

“He is a Great American,” Trump tweeted of Kelly aboard Air Force One on a rainy Friday afternoon in late July 2017. The appointment-by-Twitter caught Kelly, then the Secretary of Homeland Security, by surprise. He hadn’t even officially accepted the job, according to sources close to him.

The embattled former Republican National Committee chairman Reince Priebus was out; a retired Marine general was in.

Two months later, the president declared Kelly “one of the best people I've ever worked with." “He will be here, in my opinion, for the entire seven remaining years," Trump said.

But now, at Kelly’s one year mark on the job, that prediction about his tenure is very much in doubt.

Trump associates inside and outside the White House say Kelly has made his mark and accomplished his mission – and begun contemplating his future, increasingly taking a less public role in day-to-day presidential affairs.

President Trump in recent weeks has been conferring with associates about another possible staff shake-up. He installed a new deputy chief of staff for communications – former Fox News executive Bill Shine – who reports directly to him, not Kelly.

Sources told ABC News the president didn’t consult with Kelly on the decision to hire Shine – or the hiring of top economic advisor Larry Kudlow and National Security Adviser John Bolton.

The president has also floated names of possible Kelly successors in conversations with associates, sources familiar with the deliberations said.

Former congressman Mick Mulvaney, currently the Director of the Office of Management and Budget and Nick Ayers, current chief of staff for Vice President Mike Pence, remain the two most likely picks to succeed Kelly, the sources said.

While some sources have suggested Kelly’s departure may be imminent, others close to Kelly say he’s not quite ready to go and that the president might want him to stick around, with contentious midterm elections on the horizon and a historic Supreme Court nomination to see through.

“[John Kelly] has adopted the Rex Tillerson mantra – ‘if you want to get rid of me, fire me,’” one source close to the White House and Kelly told ABC News. “He understands that the president does not like to fire people.”

The White House declined to comment on Kelly’s status or a timeline for his expected departure.

While Trump has repeatedly said he “could not be happier” with his chief of staff who he’s applauded for “doing a fantastic job,” in recent months, Kelly has found himself in hot water with the president.

The president and some of his long-time aides have increasingly chafed at some of the restrictions Kelly imposed, including limiting access to the Oval Office, cracking down on temporary security clearances and banning personal cell phone use in the West Wing.

Kelly has also been a source of consternation for some of his public statements and perceived missteps.

After suggesting in a Fox News interview that Trump’s campaign promise to build a border wall was “uniformed,” Kelly was chastised by the president, sources said.

Several months later, amid an increasingly acrimonious relationship with his boss, he was forced to publicly deny reports alleging he privately called Trump an “idiot.”

Kelly was also at the center of a White House public relations crisis in February for his handling of allegations of domestic abuse by former staff secretary Rob Porter, whom he was grooming to become his deputy.

At the time, Trump voiced frustration over the public relations firestorm and even discussed possible replacements for Kelly. Sources said Kelly made clear to the president he was willing to resign.

“Even though John Kelly will be remembered for how he handled the Rob Porter scandal, feuding with a gold star family, and calling immigrants ‘lazy,’ he certainly did not deserve the indignity and abuse he’s had to endure from the President,” a former White House official told ABC News.

The official was referring to Trump’s habit of openly musing to confidantes about firing Kelly and leading fellow West Wing staff to speculate their boss could be on borrowed time.

“I did something wrong and God punished me, I guess,” Kelly joked about the job during an interview in March. He has famously called the chief of staff role the “hardest” and “most important job” he’s ever had.